Hello:

I have a simple question? Can the kernel be copied into the MMC card, and subsequently being booted from there? If it's not, why not?

Also, can a kernel instead be booted off an TFTP server across the network? If not, why not?

I am trying ways to leave the flashed kernel untouched.

thanks for your support.

CSanta

Please search the forums "Booting from MMC" and you will see plenty of tutorials and post.

Thank You.

Hi, thanks for that but I did read the whole thing it doesn't explain what I need. In fact I have been able to boot off MMC BUT the kernel still resides inside the device. What I am wondering is whether you can boot from a kernel that resides inside the MMC, or even better for a kernel that resides somewhere else and grab it through TFTP.

Thanks,
CS

Well I know this has been heavily discussed, but I am not sure if anyone out there is working on it. Basically yes it is possible, but it is not available for Nokia devices at this point. Someone needs to hack the bootloader I believe to alter where it looks for the kernel, but the kernel loads the ext2 support so I am not sure how that would all shake out.

I can confirm that it DOES NOT work at this point. I wanted to do this to have an original or release 2 kernel & image running for Kismet, and a release 3 kernel & image for regular use because of better video performance. See this thread for details.

FYI, this was also an issue with the Sharp Zaurus, due to which type of memory/flash held the kernel vs the userspace stuff, but I can't remember the details.

It should in principle be possible to boot from a kernel on a card, if the 'kexec' system function can be enabled in the N800 kernel. I haven't checked if it can be done. In any case if one did that it would probably be a good idea to compile a kernel with the filesystem drivers built-in, to avoid having to rely on an initrd (ram disk, used for booting) image.

Well you should be able to use Fanoush's kernel flash script and make some menu options to call the kernel flash. Then just reboot to the new kernel. pick the other menu option and boot back. Not the best solution but it would work.

The easiest way how to select from more kernels is kexec i.e. having small kernel in flash that can load full kernels from mmc or anything else. I think kexec for ARM is part of mainline kernel since 2.6.21 but there are patches for older kernels working on Zaurus and other ARM based devices. Also search this forum for 'kexec' or 'LAB', it was already mentioned. I have it in my TODO list for long time but so far didn't do any actual work. I expect there may be some extra work specific to Nokia tablets with keeping the watchdog happy when kexec-ing different kernel and also with passing parameters from Nokia
bootloader to second kernel. Also kexec is highly architecture dependent so there may be still some work to do to have it working on OMAP architecture.

So the short answer is no, it is currently not possible you can have only one kernel and in must be in /dev/mtd2 partition.

However one related thing that actually works is loading kernel to device RAM and booting it over USB without flashing. This is supported by Nokia flasher (-l option) and is somewhat similar to TFTP (i.e. not very practical for normal multiboot usage but very handy for testing experimental kernels).

Thanks for the last reply. Exactly, I need to test experimental kernels.

How come I need to boot it over USB if it's already on device RAM??? I need more info about how this works.

CS

the procedure is similar like flashing the kernel over USB but the kernel is only loaded to RAM and booted, flash is untouched so next reboot brings old kernel back