ReadyNas Duo V2 - u-boot doesn't boot any more - SOLVED

chirpa wrote:
Does this help at all?

Jepp. It does. Thanks.
At least I am able to get a u-boot console again. But I wasn't able to restore the default boot process yet. Do you have a working uboot.bin?

It boots and writes u-boot-env:

Unlocking flash...
Done
Erasing old environment...
Done
Writing environment to /dev/mtd1...
Done
Locking ...

After that it wrote kernel and initrd.
Next boot, still the same problem. I tried to supply uboot.bin as well but it now complains:

Searching for internal boot flash device...mtdblock4
Searching for external boot flash device...sda
Writing internal nand flash device...ERROR: flash image checksum does not match!!

The uboot.bin I used was an image I read from /dev/mtd0. It should have the 512 byte nand header but it does not have the 4 byte checksum at the end.
I created another u-boot image by stripping the header and applying again using doimage. this one is 4 byte larger and should have a checksum.
But it still complains about wrong checksum.

Oh no!!! I have to strip the final 4 bytes as well before applying doimage. And I cannot use the image read from /dev/mtd0 because there is a lot of garbage at the end!
I created a UART version from the uboot.bin you provided and successfully uploaded it.
But it only says:

...
NAND:128 MB
Switch On !

That's it. Are you sure it should work on the Duo V2? I would like to know before I copy it to the USB drive and burn it into NAND.

BTW: the howto says you have to format the USB drive from linux. this isn't true. I did from WinXP without problems.