I was in fact wrong that my self-compiled android kernels weren’t booting — they were. But they do fail somewhere in init:. Unfortunately, when you boot the phone, you don’t have any idea why it fails because there’s no console by default. It would’ve been a lot easier to see this if I had a serial cable, but I did finally remember that I could use fbcon with the smallest font and CONFIG_PRINTK_DELAY to see the messages scroll by. And so now I see the problem:
A N D R O I D init: Unable to open persistent property directory /data/property errno: 2 init: cannot find '/system/bin/sh', disabling 'console' init: cannot find '/system/bin/servicemanager', disabling 'servicemanager' ...
Obviously, the init script can’t mount the mtd partitions, despite the partition tables being successfully probed at start and my having yaffs2 built-in. Oh well, at least now I have a direction to start debugging.
The 2.6.25 branch of the msm tree, incidentally, works fine with the stock initrd and userland, but who wants such an old kernel? Oh, and I changed my bootup logo to a shiny Tux instead of the default robot. “Android isn’t Linux” indeed.