Dear Gerhard,
2014/1/9 Gerhard Sittig gsi@denx.de
According to `git log` and `git show b77026225a31` ("ARM : Add support for MINI2440 (s3c2440)." as of 2012-05-02) only boot from NOR is supported. Later commit 79a6fcf2573e (2013-06-15) fixed GPIO register access, and commit 2108f4c4a302 (2013-10-04) adjusted CONFIG_SYS_HZ.
Later I2C and USB got adjusted, but those changes should only have an affect after a banner was shown (that's an assumption of mine, I2C _may_ be involved in detecting the board before showing a banner). Correct clocks OTOH are a prerequisite for serial communication.
You may want to check those exact revisions identified above which changed "mini" related code, or their direct predecessors in case a change broke a feature for you. If one of those works for you, you may 'git bisect' from there, to help diagnose what needs to get improved or added to re-gain support for your board in mainline U-Boot.
Thank you for the guidance to the exact revisions where "mini" related changes were committed. I tried all of them, but I could not run the binaries on my board. In `git show b77026225a31` it is mentioned, that the git I used successfully earlier [1] was merged to the mainline U-Boot, but this one did not work neither (from NAND or RAM). I tried all the revisions you mentioned, and the direct predecessors as well, and some other I found could be related to "mini', but so far no joy.
I understand that you want to keep the current bootloader in NOR, which means that lack of support to boot from NAND only leaves you with boot from RAM, which the software may not support either (it's not as trivial as it may sound, and requires explicit support). So when the software only supports booting from NOR, and you don't have the software in NOR, this may be a reason why it doesn't work for you.
Correct. At least since I don't have a JTAG programmer I don't dare to swipe out the original 'supervivi' boot loader, as with it I can play with the NAND with no risk. In case the U-Boot I write to NOR would not work, I will brick my board till I can get a JTAG programmer. The version from [1] can be started both from RAM and from NAND without any hassle, but in the mainline log it is clearly mentioned that after integrating it supports only NOR. So far I could not find any other revision mentioning that booting from NAND or RAM was solved regarding the specific board.
I just saw that the board support was removed with the new RC released this week. So for me it seems the best idea would playing with the source tree available at [1], as it has more functions supported on my board. Anyway, thank you for your kind help!
Best regards, Peter
[1] git://repo.or.cz/u-boot-openmoko/mini2440.git