Just flashed u-boot and r121 on my C760 (was KathrinRC12); here are some comments:
u-boot
- Flashing u-boot is OK, but after, there is screen is flickering. Did not bother to fix it, so, can't say more about this.
- In order to boot after flashing the bootloader, i had to remove power sources (alim AND battery) and plug AC while holding "OK" for a few seconds.
- Had some problems with CF card: unable to read, "df -h" segfaults, ... Had to boot without the CF, then plug it, copy CF content to a SD and run autoboot.sh manually. This worked, but could be related to the card formatting.
- After flashing, the Zaurus didn't reboot. Had to unplug the power.
r121
- / is still not mounted noatime in fstab. This is bad.
- Keymap is broken: ctrl, alt, mail, home and menu doesn't work.
- When loading X then exiting, console is really weird.
- KR9 seemed faster to me.
I will report other issues soon