Quote:
Originally Posted by educosta
Oh, thought it was more common around. I've seen a post claiming the kobo can be instructed to boot from the external sd card if the home button is pressed while powering it up. So I'll locate one, write the kernel to it, and give it a go. I could send the image from the host, and flash it from within the kobo itself.
If somebody seein this happens to know the on-board pinouts of this kobo, please let me know. Very little information on this particular model out there that I've seen so far.
All I can see within the board is 7 pins in a row, with (non-populated) resistor terminations. Will check if it's jtag or usart ports or something.
Thanks!
|
Hi Edu! I think the post is mine.
You can boot using a rootfs on a external sdcard but the kernel should be loaded at that point of time. That's it: we use a key combo to override the arguments passed to the kernel but we don't modify that kernel.
It should be possible to modify uboot to load a kernel stored on a ext2 partition (or in raw disk) but isn't recommended on your case, for the following reasons:
- uboot has a watchdog that resets the board each few seconds.
- uboot has the environment hardcoded and does a CRC32 check of that environment on boot.
- messing with uboot (or replacing the kernel) in a device with soldered EMMC is a bad idea because there's no way to recover that.
If you have other device with a user-replaceable sdcard then you can go straight and copy the kernel at the same offset. But, in your case, is too dangerous.
You can check if stock kernel has kexec support. In that case you can use the trick to boot from external sdcard and use kexec there to load your new kernel.
I hope the message is clear. Have fun with your lurking.
