I can download my kernel uImage and flash it into NAND and then 'boot' and it works.

bfin> tftp 0x1000000 10.100.42.29:uImage.3 bfin> nand erase 0x80000 0x800000 bfin> nand write 0x1000000 0x80000 0x800000

Going to verify the image: bfin> nand read 0x2000000 0x80000 $(filesize) bfin> iminfo 0x2000000

## Checking Image at 02000000 ... Legacy image found Image Name: bf548-0.2-3.0.8-ADI-2011R1-dirty Created: 2012-04-15 23:30:18 UTC Image Type: Blackfin Linux Kernel Image (gzip compressed) Data Size: 5218920 Bytes = 5 MiB Load Address: 00001000 Entry Point: 0026de3c Verifying Checksum ... OK bfin>

And then I can boot: bfin> boot Loading from nand0, offset 0x800000 ** Unknown image type ## Booting kernel from Legacy Image at 01000000 ... Image Name: bf548-0.2-3.0.8-ADI-2011R1-dirty ......

And if I do a soft reset I can still boot, every time. But when I cycle the power I get this: ..... Hit any key to stop autoboot: 0

Loading from nand0, offset 0x800000 ** Unknown image type Wrong Image Format for bootm command ERROR: can't get kernel image! bfin>

my boot command is: nandboot=nboot 0x2000000 0 0x800000;run nandargs;bootm

Any ideas? This used to work :) without failure until I updated uboot from an older version to something a bit more recent.