On Tue, Feb 24, 2026 at 11:24:44AM -0600, Tom Rini wrote:
> On Tue, Feb 24, 2026 at 11:57:23AM +0000, Daniel Golle wrote:
> > On Mon, Feb 23, 2026 at 01:32:19PM -0600, Tom Rini wrote:
> > > On Tue, Feb 17, 2026 at 11:46:17AM -0600, Tom Rini wrote:
> > > > On Mon, Feb 16, 2026 at 09:21:14PM +0000, Daniel Golle wrote:
> > > > 
> > > > > Hi all,
> > > > > 
> > > > > This RFC series adds a new boot method for OpenWrt's "uImage.FIT with
> > > > > embedded rootfs" firmware model, along with the underlying 
> > > > > infrastructure
> > > > > to load FIT images on-demand directly from storage devices without 
> > > > > copying
> > > > > them entirely to RAM first.
> > > > [snip]
> > > > > AI tool disclosure
> > > > > ==================
> > > > > 
> > > > > Major parts of this series were developed with assistance from GitHub
> > > > > Copilot (Claude Opus 4.6, Anthropic). The AI was used as a coding
> > > > > partner for scaffolding boilerplate, drafting documentation and commit
> > > > > messages, running checkpatch sweeps, and iterating on review feedback.
> > > > > All architectural decisions, U-Boot subsystem integration, hardware
> > > > > testing, and final review were done by the human author. Every line of
> > > > > code was reviewed and tested on real hardware before inclusion.
> > > > 
> > > > First, I appreciate your honesty and explanation in the disclosure here.
> > > > 
> > > > This topic comes up, and will keep coming up, and as a project we have
> > > > not yet decided on a position. I know that the Linux Kernel has come up
> > > > with:
> > > > https://docs.kernel.org/next/process/generated-content.html
> > > > so far. But I think that:
> > > > https://docs.postmarketos.org/policies-and-processes/development/contributing-and-ai.html
> > > > brings up points that are quite relevant too. Absolutely no one has been
> > > > happy with when gitlab or patchwork were unusable / unreachable (and for
> > > > some people are still unusable) but it's because of all the AI scrapers
> > > > that things were unusable or now have anubis in front of them (blocking
> > > > other humans now).
> > > > 
> > > > With that said, I want to stress the "human is responsible" portion of
> > > > what both links say, and that given where exactly these changes are
> > > > aimed for, extra scrutiny is required. Things like:
> > > > https://cyberplace.social/@GossiTheDog/116080909947754833
> > > > show just how bad they are about introducing security bugs these days.
> > > 
> > > Following up on this part I suppose, I see in CI you're working on v2
> > > but please make sure to follow up with the other outstanding questions
> > > I've asked before posting that. Thanks!
> > 
> > I've carefully reiterated over all your emails regarding the series and
> > my replies to them. Apart from your request to share an image making use
> > of the proposal to include dm-verity parameters in uImage.FIT (and use
> > the presence to decide whether has varifications of that subimage may be
> > skipped) I haven't found anything which hasn't been answered. But maybe
> > I missed something, of course.
> 
> There's:

Thanks for digging all of them out. I took the freedom to answer all of
them here as it makes it easier to keep track of all the topics being in
a single thread.

> https://lore.kernel.org/u-boot/20260217150820.GB2747538@bill-the-cat/
> And I see you're using CI, but I didn't see an ack about the size
> investigations portion.

I had to remove the -E (errors-as-warnings) option from the script
because my host toolchain is too new and caused a few warnings about
discarded 'const' qualifiers. Most can be fixed by updating dtc to
that in upstream Linux, the other one is in
    tools/atmelimage.c:64:31: error: assignment discards ‘const’ qualifier from 
pointer target type [-Werror=discarded-qualifiers]
and can also be fixed easily. I'll post the patch for that after I
send this email.

Updating dtc, however, caused a cascade of new warnings in existing
device tree files, newly introduce node-name checks, ... so at that
point I decided to just remove the -E option passed from the script
to buildman...

Results:
For any board having CONFIG_FIT enabled but none of the new features
there is a slight increase:
   aarch64: (for 1/1 boards) all +8.0 text +8.0
            mt7622_rfb     : all +8 text +8
               u-boot: add: 0/0, grow: 1/0 bytes: 8/0 (8)
                 function                                   old     new   delta
                 fit_image_load                            1632    1640      +8

The increase by 8 bytes is caused by this hunk:
--- a/boot/image-fit.c
+++ b/boot/image-fit.c
@@ -2279,8 +2362,9 @@ int fit_image_load(struct bootm_headers *images, ulong 
addr,
                        return -EXDEV;
                }
 
-               printf("   Loading %s from 0x%08lx to 0x%08lx\n",
-                      prop_name, data, load);
+               if (data != load)
+                       printf("   Loading %s from 0x%08lx to 0x%08lx\n",
+                              prop_name, data, load);
        } else {
                load = data;    /* No load address specified */
        }

It could obviously also be guarded by some
if (!CONFIG_IS_ENABLED(IMAGEMAP) || data != load)
so the compiler would end up with byte-identical code in case
CONFIG_IS_ENABLED(IMAGEMAP) is false.
Do you think that'd be worth it?

Enabling the new features for the BanananPi R3 required also enabling
CONFIG_FIT which previously wasn't selected for that board.
With all the new options (CONFIG_FIT, all imagemap backends, OpenWrt bootmeth):
   aarch64: (for 1/1 boards) all +47701.0 data +848.0 rodata +5001.0 text 
+41852.0
            mt7986a_bpir3_emmc: all +47701 data +848 rodata +5001 text +41852
               u-boot: add: 142/0, grow: 22/-1 bytes: 27785/-4 (27781)
                 function                                   old     new   delta
                 MD5Transform                                 -    2528   +2528
                 fit_image_load                               -    1980   +1980
                 fit_print_contents                           -    1228   +1228
                 fit_verity_build_params                      -     948    +948
                 fit_image_print                              -     780    +780
                 cmdline_set_arg                              -     688    +688
                 imagemap_map                                 -     640    +640
                 bootmeth_vbe_ft_fixup                        -     640    +640
                 bootm_run_states                          1908    2436    +528
                 fit_image_verify_with_data                   -     520    +520
                 openwrt_boot                                 -     516    +516
                 sha256_finish                                -     404    +404
                 image_locate_script                        272     668    +396
                 boot_get_fdt_fit                             -     396    +396
                 fit_image_print_data                         -     392    +392
                 boot_get_loadable                            -     384    +384
                 fdt_check_full                               -     332    +332
                 bootm_help_text                            910    1234    +324
                 sha1_finish                                  -     300    +300
                 bootflow_scan_next                         424     724    +300
                 bootmeth_vbe_simple_ft_fixup                 -     288    +288
                 hash_command                               188     468    +280
                 hash_algo                                    -     280    +280
                 fit_all_image_verify                         -     272    +272
                 bootmeth_vbe_simple_probe                    -     264    +264
                 MD5Update                                    -     260    +260
                 do_imgextract                              668     924    +256
                 boot_get_fdt                               592     848    +256
                 static.sha1_update                           -     240    +240
                 boot_get_ramdisk                           480     720    +240
                 static.CSWTCH                              139     371    +232
                 copy_in                                      -     228    +228
                 fit_image_get_data                           -     224    +224
                 static.sha256_update                         -     220    +220
                 fit_conf_get_node                            -     216    +216
                 imagemap_map_to                              -     212    +212
                 openwrt_read_bootflow                        -     204    +204
                 fit_conf_get_prop_node                       -     192    +192
                 MD5Final                                     -     188    +188
                 imagemap_record                              -     180    +180
                 imagemap_create                              -     176    +176
                 fit_image_print_verification_data            -     176    +176
                 source_help_text                            40     212    +172
                 event_notify                                 -     168    +168
                 vbe_simple_fixup_node                        -     164    +164
                 bootflow_cmdline_set_arg                     -     164    +164
                 fit_check_format                             -     152    +152
                 vbe_get_blk                                  -     148    +148
                 vbe_read_nvdata                              -     140    +140
                 ofnode_add_subnode                           -     140    +140
                 imagemap_cleanup                             -     136    +136
                 fit_image_verify                             -     136    +136
                 fit_image_get_address                        -     136    +136
                 ofnode_copy_props                            -     120    +120
                 boot_get_setup_fit                           -     120    +120
                 _u_boot_list_2_uclass_driver_2_imagemap       -     120    +120
                 _u_boot_list_2_driver_2_vbe_simple           -     120    +120
                 _u_boot_list_2_driver_2_bootmeth_openwrt       -     120    
+120
                 next_glob_bootmeth                           -     116    +116
                 fit_parse_subimage                           -     116    +116
                 fit_parse_conf                               -     116    +116
                 calculate_hash                               -     116    +116
                 vbe_simple_get_state_desc                    -     112    +112
                 sha1_csum_wd                                 -     112    +112
                 ofnode_write_prop                            -     112    +112
                 imagemap_lookup                              -     112    +112
                 hash_lookup_algo                             -     112    +112
                 vbe_simple_read_state                        -     100    +100
                 vbe_read_version                             -     100    +100
                 vbe_find_first_device                        -      96     +96
                 uimage_phase                                 -      96     +96
                 ofnode_write_u32                             -      96     +96
                 md5_wd                                       -      96     +96
                 genimg_get_kernel_addr_fit                  24     120     +96
                 imgextract_help_text                        85     178     +93
                 board_init_r                               572     664     +92
                 vbe_find_next_device                         -      88     +88
                 simple_read_nvdata                           -      88     +88
                 sha256_starts                                -      88     +88
                 fit_get_node_from_config                     -      88     +88
                 bootmeth_get_bootflow                        -      88     +88
                 bootflow_check                               -      88     +88
                 bootmeth_setup_iter_order                  284     368     +84
                 bootmeth_glob_allowed                        -      84     +84
                 board_init_f                              1168    1252     +84
                 image_info                                 208     288     +80
                 get_table_entry_id                           -      80     +80
                 fit_image_hash_get_value                     -      80     +80
                 fit_image_get_emb_data                       -      80     +80
                 fit_image_get_type                           -      76     +76
                 fit_image_get_phase                          -      76     +76
                 fit_image_get_os                             -      76     +76
                 fit_image_get_arch                           -      76     +76
                 bootflow_cmdline_set                         -      76     +76
                 sha256_csum_wd                               -      72     +72
                 fit_image_get_node                           -      72     +72
                 fit_image_get_data_size                      -      72     +72
                 fit_image_get_data_position                  -      72     +72
                 fit_image_get_data_offset                    -      72     +72
                 fit_image_get_comp                           -      68     +68
                 vbe_reqs                                     -      64     +64
                 sha256_padding                               -      64     +64
                 sha1_padding                                 -      64     +64
                 image_setup_libfdt                         344     408     +64
                 hash_finish_sha256                           -      64     +64
                 hash_finish_sha1                             -      64     +64
                 fit_image_check_type                         -      60     +60
                 fit_image_check_os                           -      60     +60
                 fit_image_check_comp                         -      60     +60
                 fit_conf_get_prop_node_index                 -      60     +60
                 do_source                                   84     144     +60
                 crc32_wd_buf                                 -      60     +60
                 crc16_ccitt_wd_buf                           -      60     +60
                 sha1_starts                                  -      56     +56
                 openwrt_bootmeth_ops                         -      56     +56
                 oftree_path                                  -      56     +56
                 ofnode_write_string                          -      56     +56
                 hash_finish_crc32                            -      56     +56
                 hash_finish_crc16_ccitt                      -      56     +56
                 fit_image_hash_get_algo                      -      56     +56
                 fit_get_desc                                 -      56     +56
                 bootmeth_vbe_simple_ops                      -      56     +56
                 hash_update_crc32                            -      52     +52
                 hash_update_crc16_ccitt                      -      52     +52
                 hash_init_sha256                             -      52     +52
                 hash_init_sha1                               -      52     +52
                 crc8                                         -      52     +52
                 hash_init_crc32                              -      48     +48
                 hash_init_crc16_ccitt                        -      48     +48
                 alist_uninit                                 -      48     +48
                 openwrt_bootmeth_bind                        -      44     +44
                 bootmeth_vbe_simple_bind                     -      44     +44
                 openwrt_check                                -      36     +36
                 imagemap_post_probe                          -      36     +36
                 hash_update_sha256                           -      36     +36
                 hash_update_sha1                             -      36     +36
                 vbe_simple_read_file                         -      32     +32
                 openwrt_bootmeth_ids                         -      32     +32
                 generic_simple_vbe_simple_ids                -      32     +32
                 bootflow_scan_first                        236     264     +28
                 genimg_get_type_id                           -      24     +24
                 genimg_get_phase_name                        -      24     +24
                 genimg_get_phase_id                          -      24     +24
                 genimg_get_os_id                             -      24     +24
                 genimg_get_comp_id                           -      24     +24
                 genimg_get_arch_id                           -      24     +24
                 fit_image_get_load                           -      16     +16
                 fit_image_get_entry                          -      16     +16
                 fit_get_end                                  -      16     +16
                 bootm_find_images                          268     284     +16
                 
_u_boot_list_2_evspy_info_2_EVT_FT_FIXUP_3_bootmeth_vbe_simple_ft_fixup       - 
     16     +16
                 
_u_boot_list_2_evspy_info_2_EVT_FT_FIXUP_3_bootmeth_vbe_ft_fixup       -      
16     +16
                 sha256_update                                -      12     +12
                 sha1_update                                  -      12     +12
                 genimg_get_kernel_addr                      20      32     +12
                 event_type_name                              -      12     +12
                 event_notify_null                            -      12     +12
                 vbe_simple_read_bootflow                     -       8      +8
                 vbe_req_random_seed                          -       8      +8
                 vbe_req_efi_runtime_rand                     -       8      +8
                 vbe_req_aslr_rand                            -       8      +8
                 vbe_req_aslr_move                            -       8      +8
                 oftree_root                                  -       8      +8
                 genimg_has_config                            8      16      +8
                 boot_get_setup                               8       4      -4

This seems excessive, but it's mostly due to CONFIG_FIT not being enabled
in the upstream U-Boot defconfig for the BananaPi R3.

With CONFIG_FIT enabled already before, the changes are more reasonable:
   aarch64: (for 1/1 boards) all +6057.0 data +296.0 rodata +513.0 text +5248.0
            mt7986a_bpir3_emmc: all +6057 data +296 rodata +513 text +5248
               u-boot: add: 21/0, grow: 3/0 bytes: 5336/0 (5336)
                 function                                   old     new   delta
                 fit_verity_build_params                      -     948    +948
                 cmdline_set_arg                              -     688    +688
                 imagemap_map                                 -     640    +640
                 openwrt_boot                                 -     516    +516
                 fit_image_load                            1632    1980    +348
                 copy_in                                      -     228    +228
                 imagemap_map_to                              -     212    +212
                 openwrt_read_bootflow                        -     204    +204
                 imagemap_record                              -     180    +180
                 bootm_run_states                          2256    2436    +180
                 imagemap_create                              -     176    +176
                 bootflow_cmdline_set_arg                     -     164    +164
                 imagemap_cleanup                             -     136    +136
                 _u_boot_list_2_uclass_driver_2_imagemap       -     120    +120
                 _u_boot_list_2_driver_2_bootmeth_openwrt       -     120    
+120
                 imagemap_lookup                              -     112    +112
                 bootflow_cmdline_set                         -      76     +76
                 openwrt_bootmeth_ops                         -      56     +56
                 alist_uninit                                 -      48     +48
                 openwrt_bootmeth_bind                        -      44     +44
                 openwrt_check                                -      36     +36
                 imagemap_post_probe                          -      36     +36
                 fit_image_get_data                         188     224     +36
                 openwrt_bootmeth_ids                         -      32     +32


> 
> There's:
> https://lore.kernel.org/u-boot/20260217192000.GH2747538@bill-the-cat/
> And I didn't see anything about that.

Re: boot: add OpenWrt boot method and on-demand FIT loading

(Re: not enabled on any board nor in sandbox)
In my new series I'll add the OpenWrt One as a sample board and also
enable the new features on the BananaPi R3.

Should I also enable the imagemap base feature in sandbox as well so the
unit tests can easily be run?

(Re: splitting series)
There aren't any actual fixes part of the series. Of course, some
smaller changes and refactoring to create the helpers needed by
imagemap and the bootmeth could be broken out as indidivual patches
sent separately in advance, but they wouldn't have any in-tree users
at this point. Eg.
 - mtd: set flash_node on DT-created partitions
 - mtd: add mtd_read_skip_bad() helper
 - cmd: ubi: add ubi_part_from_mtd()
 - cmd: ubi: export ubi_find_volume()

I also think it makes sense to discuss the new feature (not part of the
original RFC series) to store dm-verity parameters for IH_TYPE_FILESYSTEM
subimages in the FIT structure separately, and that would start with
discussing the FIT spec amendment for it:

https://github.com/open-source-firmware/flat-image-tree/pull/37

> There's:
> https://lore.kernel.org/u-boot/20260217190554.GF2747538@bill-the-cat/

Re: test: boot: add image_loader unit tests
(Re: AI fixes in the wrong commit)
Yes, this was an oversight and I've of course folded in that change,
and later, upon Simon's comment, switched to use alist instead of a
fixed-size array anyway.

> https://lore.kernel.org/u-boot/20260219153100.GL3233182@bill-the-cat/
> Which go together and I think "human written only commit message" might
> well be a good policy as it helps ensure the patch in question has been
> read and summarized by the human author (and enforcement is on the
> honor system).

While it was very useful to use an LLM for quickly drafting the intial
RFC and receive feedback for the overall approach, it became less and
less useful at later stages -- instead of ending of micro-managing the
LLM for each little change and fix it's easier to just do it yourself
from some point on.

So what you are going to see in v2 surely still got some onchanged lines
of code, comments and parts of commit messages which have intially been
fabricated with the help of the LLM, but most of it is by now the work
of a human (me).

Regarding the commit messages, I get the idea of enforcing a
human-written message, however, when it comes to the use of English
language (I'm not a native speaker) I think the use of things like
deepl.com does create more benefit than potential damage even though it
can also be considered an AI/LLM tool.


> Finally there's:
> https://lore.kernel.org/u-boot/20260217191536.GG2747538@bill-the-cat/
> where I was hoping for more feedback.
Re: reuse imageloader (by now renamed to "imagemap") in SPL

First of all, I don't have any boards which use SPL. All modern
platforms I deal with use U-Boot as "Non-Trusted Firmware (BL33)" or
the OpenSBI equivalent of that on platforms using RISC-V.

Especially regarding the UBI part, the implementation intended for SPL
is way too basic to be useful as imagemap backend.

For BLK (ie. MMC) or SPI-NOR it would be a possibility to reuse
imagemap in SPL -- but (as I've replied earlier) I don't think it
makes sense to merge it with the exising FIT reader in SPL for the
reasons I've explained:
|> So there really isn't much overlap other than the fact that there is a
|> struct with a priv pointer and a .read callback, and even that uses a
|> different addressing parameter (sectors vs. bytes).


> I don't recall if we came to a conclusion, or just look again later,
> about if we should have this functionality both exposed via "bootm" and
> the new distro bootmeth, or not. It might be "talk more" and I'm leaning
> currently on saying the migration path is something openwrt holds
> downstream while getting things migrated?

That's also what I understood from our discussion. Adding new cmdline
features to 'bootm' can be considered a liability, so I've dropped that
from the v2 series and only use the direct-storage FIT loading in
bootmeth_openwrt. We can still add the 'bootm' features as an
intermediate step to easy migration of all our boards as downstream
patch (and later remove it again once all boards and features work with
the bootmeth).

> And in sum, this series will need to be split up a bit I strongly
> suspect. Being clear about the end goal is good but implementing each of
> the backends as well in a single series will make this too large to
> review.

The current state of the series looks pretty much like what I've pushed
to Github for the sake of getting CI exposure.

Do you agree with the submission strategy drafted below?

Commits (reverse git order, starting from the one directly
on top of u-boot.git master branch, ie. in the order of
the patches to be submitted starting with the first to be
sent).

SERIES 1: dm-verity paramters for FIT images

 - boot: fit: support generating DM verity cmdline parameters
 - doc: fit: add dm-verity boot parameter documentation

To be discussed together with
https://github.com/open-source-firmware/flat-image-tree/pull/37
---
SERIES 2: imagemap storage abstraction

 - boot: add imagemap on-demand loading abstraction
 - boot: imagemap: add block device backend
 - doc: imagemap: document on-demand loading framework
 - test: boot: add imagemap unit tests

This would be a meaningful series together with enabling imagemap
in sandbox so the unit tests are run there.
---
SERIES 3: imagemap MTD and UBI backends

 - mtd: add mtd_read_skip_bad() helper
 - boot: imagemap: add MTD backend
 - mtd: set flash_node on DT-created partitions
 - cmd: ubi: export ubi_find_volume()
 - cmd: ubi: add ubi_part_from_mtd()
 - boot: imagemap: add UBI volume backend

This would be one or two small series adding the backends.
Maybe including another commit completing the documentation
to cover the newly added backends.
---
single PATCH

 - boot: fit: support on-demand loading in fit_image_load()

This would be good to be discussed individually as it is
the most intrusive change and needs the most eyeballs.
---
SERIES 4: OpenWrt boot method

 - boot: bootmeth: add OpenWrt boot method skeleton
 - boot: bootmeth: openwrt: implement read_bootflow
 - boot: bootmeth: openwrt: implement boot via imagemap
 - boot: bootdev: add MTD boot device
 - boot: bootdev: add UBI boot device
 - doc: bootstd: add OpenWrt boot method documentation
 - board: mediatek: add OpenWrt One support
 - mt7986a-bpi-r3: add OpenWrt boot method


Cheers


Daniel

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