Comment 4 for bug 435046

Michael,

I was just able to download u-boot from u-art to the DDR using minicom.
This way you will never be able to brick your u-boot on the SPI flash since you can always recreate it.

The process is -
1. Build U-boot for uart configuration. The 512MB configuration worked for me but the 1GB didn't (on u-boot version 4.2.9) - bug was reported and will be fixed in future releases.
2. Open minicom with 115200 8N1 no HW/SW flow controls
3. Modify boot option to boot from uart (dip switch SW7 set to 0xe)
4. Power up the system. The bootrom should send NACK character which is translated as space character on minicom
5. Hold the reset button
6. Send the u-boot in xmodem (Ctrl-A - S, choose xmodem and then file).
7. Release the reset button. Note that the board should stay at reset when starting sending the file.

If after xmodem file send is done and you still get the space characters in minicom (and not u-boot prompt) then it means that checksum on the image failed !!!

After u-boot is booted through uart and loaded to DDR, you can 'bubt' your new brand u-boot but with booting from SPI configuration; resetenv and all other goodies you want.

Michael - please let me know if you want other info on this; or should I post this info on different place.