Wakelocks

Posted Dec 24, 2011 6:20 UTC (Sat) by dlang (guest, #313)
In reply to: Wakelocks by neilbrown
Parent article: Bringing Android closer to the mainline

the fact that I can't easily use the features that are in a kernel.org kernel with android userspace is one big barrier.

even if I am trying to compile my own android kernel, there doesn't seem to be any way of installing it on a device in a way that will let me fall back to the older kernel if I run into problems with the new one (the equivalent to the old lilo -R option)

the integration of things into the mainline will greatly help the first problem, but I still don't know a good solution for the second one.

Wakelocks

Posted Dec 24, 2011 11:50 UTC (Sat) by mjg59 (subscriber, #23239) [Link]

If you hit problems you just drop back to recovery and flash the old kernel back. Alternatively, do your testing using fastboot to push the kernel and ramdisk over USB and don't touch your flash at all.

Wakelocks

Posted Dec 24, 2011 12:30 UTC (Sat) by Cyberax (✭ supporter ✭, #52523) [Link]

You can use kexec, but I don't bother. On Galaxy S phones it's always possible to drop into "download mode" and just restore the old kernel image.

It's _always_ possible even if your firmware is totally corrupted and even battery controller is dead. In some cases it requires a magic jig, though (a 101kOhm resistor shorting two USB lines).

Wakelocks

Posted Mar 19, 2012 14:14 UTC (Mon) by jimmyflip (guest, #83547) [Link]

It's hard to imagine anyone doing even a small amount of Android kernel development wouldn't use 'fastboot boot' to test their kernel (assuming they have a capable bootloader). Any problems, just reboot.