how does ur item file look like.........cant ansa ya question.....tanks

I actually didn't use an item file to boot Nemo (wouldn't have been possible since I don't have access to the eMMC without starting Nemo).

I am actually not sure whether I used item file or run sdboot.
But here is my item file:
Did you copy the kernel (exactly named as in item file) to /etc/bootmenu.d and ran u-boot-update-bootmenu?

Extended question (might be a bit off topic): How would I boot RescueOS off of the SD card using U-Boot?

Edit: Got it. Slightly complicated, though. And for some odd reason, I can't mount rootfs (it complains about "no such device", though the device is clearly there...)

Generate uImages for both the kernel and the initrd images. Copy those onto the SD card, then put in the SD card and boot. Choose console when asked. Then, type:
(assuming SD card is fat32 formatted):

mmc dev 0
fatload mmc0 0 0x82000000 (path to kernel file)
fatload mmc0 0 0x83000000 (path to initrd file)
setenv bootargs 'rootdelay root=/dev/ram0'
bootm 0x82000000 0x83000000

It should then load. Still need to figure out how to modify rootfs, though.

Edit 2: I wonder, if one could load the maemo kernel and bypass whatever's causing the crash that way...

Edit 3: Tried it with the kernel image in eMMC under bootmenu.img.d. Didn't work. Next step: See if I can get a kernel + maemo rootfs onto an SD card and boot it that way. Probably not, but it's worth a shot (and if it works, the SD card would contain flasher, and I can reflash the kernel at last...)

Edit 4: Tried booting the framebuffer kernel. It seems to boot, but gets stuck at "waiting for root device /dev/mmcblk0p1" (primarily because I had the "rootwait" parameter in place to avoid the kernel crashing from not find the rootfs). As the main rootfs now has Kernel Power v51r1 (and so I can't get it to boot with the framebuffer kernel - and even if I could, I have a feeling it would crash instantly on startup since I also have CSSU-Thumb), this might be tricky. Does Kernel Power support framebuffering? If so, does anyone have a copy I could load from an SD card? (not a fiasco image - that doesn't really work for this purpose).

Edit 5: Unsurprisingly, it can't find root if I don't put in that option. Slightly annoying. Well, time to see if I can try something else...

Edit 6: Could it be possible that the latest version of U-boot doesn't initialize rootfs on certain hardware correctly? Upon trying to mount it, I get:
cannot open ubi0:rootfs, error -19
And the kernel panics afterwards. This is before the kernel modules even come online, which is quite interesting.

Edit 7: Just did a kernel compile with ext2, ext3, fat, mmc, etc., built in, as per: http://talk.maemo.org/showthread.php?t=83719. It starts without boot options, but seems to just stall after recognizing the sd card and the internal mmc (and eventually, the N900 shuts down). Will specify own boot options later.

Edit 8: It actually sees the mmc card, but it gets stuck at waiting for the rootfs - despite the fact that the rootfs at that time had already loaded. Odd.

Edit 9: Turns out that I forgot to compile in MMC Block drivers into the kernel (as oppose to it being a module). Oh well. Another recompile, coming up.

Edit 10: Got it to start! However, it crashed afterwards with a "Device Malfunction" error. Something about the preinit not being able to create a file in /sys. Well...

Edit 11: It's complaining about missing stuff on /proc and /sys. Strangely enough, my backupmenu backups don't contain the contents of these two folders (they're completely blank in the backup), and neither does the blank backupmenu image provided at the backupmenu site. I'd probably need a full rootfs clone, but those evidently aren't actually provided.

Edit 12: I managed to skip preinit after replacing /sbin/preinit with /bin/sh. While this does load a shell, it somehow doesn't turn off the watchdog/whatever that shuts the device off after 15 seconds. I tried running flasher without its arguments (to have it print a list of possible switches), and it randomly switched off after having printed this. My guess is that something must be loaded for that sequence to switch off? (As having /sbin/preinit run doesn't cause the same issue). Keymaps are also a bit messed up - I can't type in numbers at all, and so I can't switch init states to see if that's the cause.

Also, before I continue any further with this: Does flasher rely on anything which occurs after /sbin/preinit (such that I could, say, permanently brick the device if I decided to flash another a fiasco image with it without running preinit)?

added ITEM_FSTYPE="ext4".. same error

it might be the problem.. can u please explain how to do it.. i looked at all of the guides that i found (a, b and c) but cant remember seeing how to do that format..

many thanks

Never tried but with bootmenu .item file, I suppose you can obtain what you want configuring the entries:
ITEM_NAME=...
ITEM_KERNEL=...
ITEM_INITRD=...
ITEM_CMDLINE=...

From U-Boot console you have already found out the correct commands.

Yes PKv51 supports FB, but it is a loadable module (insmod, modprobe) so you must boot from an initrd to load the module, or you must recompile a PKv51 with FB embedded.

You are the second man with this error, please read at this thread from post 437.

So your supposition could be be true.

On my HW rev 2101 I have no problems with rootfs and last u-boot.

Latest nemo kernel booting happily, finally
I still can't boot omap1 or any other kernel due to the same problem as reinob had, http://talk.maemo.org/showpost.php?p...&postcount=443

@reinob: do you have any idea how i can get Maemo to boot? i'm getting the same ubifs_get_sb and unknown_block(0,0) etc

/sys and /proc are not normal folders. They are exposed by the kernel and mounted by /sbin/preinit:

You need to disable the watchdogs (use the flasher, on the PC)

The flasher just sends the rootfs to NOLO which does the flashing itself. Meaning whatever you break on the rootfs (as well as the kernel partition) you can always flash again, that is, assuming that your USB port is working OK

Good luck, and keep us posted!

Frankly, I don't know what the problem is. My bricked N900 is currently sitting in a drawer, until I find the chance to continue trying to unbrick it (may be months

In any case, on my "problematic" N900 I have U-boot 2012.04-1 (i.e. not the very latest version), and both OMAP and KP51 kernels load OK (using the standard .item files). They even mount the rootfs fine. My problem is that /sbin/preinit is broken so I can't continue from there.

I get those ubifs-related errors when I try booting the kernel "manually" from U-boot, i.e. giving manually a command line to the kernel. It may be that I made a typo, or that I didn't fully type the full command line (I tend to be overconfident when deciding what's relevant and what's not , or it may actually be a bug in U-boot when manually setting the kernel command line. I don't know at the moment.

Obviously my post is not very helpful . I do hope that you or anyone having this problem and/or the curiosity will have the time to investigate this stuff and post any findings here!

help..!
i cant install pali's uboot.. it said "unable to install uboot tools incompatible application package.."
am i missing something..? Tia..