Hi George, On Thu, Mar 21, 2019 at 05:10:38PM -0600, George Hilliard wrote: > My version of U-Boot complains if I compile out LZMA support: > --- > => tftpboot 0x81000000 uImage; tftpboot 0x84000000 hawkeye.dtb; bootm > 0x81000000 - 0x84000000 > (snip) > Bytes transferred = 7349 (1cb5 hex) > ## Booting kernel from Legacy Image at 81000000 ... > Image Name: Linux-5.1.0-rc1 > Image Type: MIPS Linux Kernel Image (lzma compressed) > Data Size: 1465871 Bytes = 1.4 MiB > Load Address: 80000000 > Entry Point: 80344338 > Verifying Checksum ... OK > ## Flattened Device Tree blob at 84000000 > Booting using the fdt blob at 0x84000000 > Uncompressing Kernel Image ... Unimplemented compression type 3 > exit not allowed from main input shell. > => > ---
There you're using a uImage though, which is different to CONFIG_SYS_SUPPORTS_ZBOOT. Even without CONFIG_SYS_SUPPORTS_ZBOOT enabled, you can build either a compressed or uncompressed uImage. Some platforms enable one of those targets by default but it doesn't appear that ralink does, so I guess you're specifying a uImage.lzma target when building the kernel? Try doing that when CONFIG_SYS_SUPPORTS_ZBOOT isn't enabled - it'll still generate the same type of LZMA-compressed uImage. What CONFIG_SYS_SUPPORTS_ZBOOT does is produce a program (vmlinuz) which contains a compressed version of vmlinux.bin along with some code to decompress it. The decompression is performed by vmlinuz itself, not by U-Boot. A uImage in contrast is just the compressed (or uncompressed) vmlinux.bin with a header prepended that U-Boot uses to understand what it's loading. If the header says the data is compressed with LZMA then U-Boot will need to support LZMA decompression. What U-Boot is complaining about there is that you gave it a uImage that's LZMA compressed & your build of U-Boot itself doesn't support LZMA. That has nothing to do with CONFIG_SYS_SUPPORTS_ZBOOT or whether the kernel binary itself supports any particular compression algorithm - it's purely down to the configuration of your copy of U-Boot. Options would be to rebuild U-Boot with LZMA support enabled, or to use a different compression for your uImage that U-Boot already supports. eg. you could specify that you want to use gzip: $ make ARCH=mips uImage.gz That would give you an image that will work so long as U-Boot supports gzip decompression, or: $ make ARCH=mips uImage.bin That would give you an uncompressed uImage which U-Boot always supports. Now it could still be valid to select CONFIG_SYS_SUPPORTS_ZBOOT if you had a need for a better compression algorithm & couldn't update your bootloader to support it, but that would be solving a different problem than your commit message claims & it wouldn't matter at all whether the bootloader supports a particular compression algorithm. Thanks, Paul