Am Sonntag, 28. Oktober 2018 schrieb Dr. Nikolaus Klepp: > Hi all! > > Today I tried to get bluetooth working on the PRiW0, which led me down a > different rabbithole in the lands of "devuan vs. raspbian". First the > findings: > > Devuan: > - /dev/ttyACM0 appears always, either accessable on GPIO14/15 or via > something unknown (should be bt). > - /dev/ttyS0 apperars only, when the "pi3-miniuart-bt" overlay is loaded. > ttyS0 is then on gpio14/15, ttyACM0 is visible but connected to someting > unknown (should be bt). > - Whatever device shoud be connected to bt, it is not: htcattach always times > out. > - "enable_uart=1" crashes the bootloader (not the kernel - that is not even > loaded at that point). In fact, anything "enable=XXX" crashes the bootloder. > > Raspbian: > - both devices work as documented by the raspbianpi foundation either on > gpio14/15 or bt. > - hciattach initializes bluetooth. > - "enable_uart=1" prevents the diappearance of "/dev/ttyS0" (which is renamed > to serial0 by systemd) > > Both systems run the same kernel, the same firmware (updated with > "rpi-update" and firmware tree copied over from raspbien). > > The only differences in the system layout (apart from systemd vs. sysv) I > found were these: > - Raspbian has an extra file /boot/LICENSE.oracle > - Raspbian FAT partition starts at block 8192, while Devuan starts at 2048. > But only the first block is used, all other are zero. > > Running out of ideas I copied all files from the devuan root partition over > to the raspbian root partition and booted the system. Guess what: The boot > process without systemd is 10 seconds faster AND bluetooth is working! > > But this fishy: all binary files in /boot are identical (devuan/rasbian), so > the bootloader and kernel sould have shown the same behaviour, i.e. either > crash or work on both systems when "enable_uart=1". And ttyS0 and ttyAMA0 > sould behave identical, but they don't. Why? Where's the difference that > matters? > > And the more pressing question: As now devuan is installed over the cops of > raspbian, who can I figure out what files are used on startup? The bluetooth > init probram is definitly a resurrected part of raspbian, but what else? > > > Nik > > > >
Forget the last questions ... I just deleted the canibalized root and transpanted my devuan rootfs (2. partion on image). Guss what? It boots, "enable_uart=1" works, I have now ttyS0 on gpio14/15 and ttyAMA0 on bluetooth without any overlay. So it comes down to this: on the RPiW0, the first partitio absolutely must start at 8192, or bluetooth won't work. My Layout is now is this: /dev/mmcblk0p1 8192 97889 89698 43.8M c W95 FAT32 (LBA) /dev/mmcblk0p2 98304 3872767 3774464 1.8G 83 Linux I'm quite sure that the first partition must be exact that size and type. Most likely that is also true for RPi3+ (and that's why I did not get the devuan image running). I think it would be a good idea to create a devuan image for rpi0 with exactly these changes :-) Nik -- Please do not email me anything that you are not comfortable also sharing with the NSA, CIA ... _______________________________________________ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
