[maemo-developers] Debian on the n900 / Configuring NOLO

[From: Frantisek Dufka]

Kimmo Hämäläinen wrote:
> On Thu, 2009-11-26 at 05:10 +0100, ext Christopher Allan Webber wrote:
>> However, I realize I need to configure the bootloader to load off the SD
>> card.  This is proving a bit hard to do, however, as I cannot find any
>> documentation on configuring the NOLO bootloader.  So even if I install
>> the system, I don't know how to get it to boot!  :)

This was not possible (or documented if possible) on previous devices. 
It would be great to have bootloder configurable. But anyway, it is 
quite unlikely there is mmc and ext2 support inside NOLO.

Workaround was changing root early in boot sequence. For previous 
devices it was like this even for stock system - initfs (/dev/mtd3) is 
set as root in kernel command line and it does some initialization and 
then does pivot_root into real root (/dev/mtd4). bootmenu was the 
solution. See https://wiki.maemo.org/Booting_from_a_flash_card

With N900 initfs is not used (even if currently present on device !?) 
and root is hardcoded in kernel command line. Initial bootmenu changes 
for N900 is there but I am still not sure whant option is the best when 
there is no initfs.

The current easy way is to change /sbin/preinit in rootfs in flash but 
it is not optimal.

I am thinking about some way to modify kernel command line in currently 
flashed kernel on the fly and possibly also attaching small initramfs 
filesystem to it. Any tips regarding this would be helpful. I guess 
unzipping, changing commandline and re-gzipping and reflashing kernel is 
doable but I am not sure if initramfs can be attached to kernel or it 
needs to be loaded by bootloader separately.

>>
>> Advice on this is appreciated.  (Any other advice to heed while
>> exploring this I am receptive to hearing as well...)
> 
> Did you try giving it as the kernel command line:
> ./flasher -broot=/dev/mmcblk1

Is this commandline stored somewhere in config partition for N900? It 
would be great to have it there. Sounds like good enhancement request 
for bugzilla :-)

So far the -b option was only one time option when you have usb cable 
with flasher attached so it is not usable for changing boot sequence 
permanently.


> Didn't work for me, though. It seems the kernel module needed for the
> memory cards is not loaded yet.

True. mmc interface is compiled as module now. I wonder why (when 
considering that we have one mmc card hardwired inside).

Frantisek