[U-Boot] U-Boot hangs when starting kernel

[scrawl at baseoftrash.de]

Hello

I want to exchange RedBoot with UBoot on a TX25 module to improve the boot time. I managed to install UBoot, but, the kernel does not start. Everything goes ok but after "Starting kernel ..." nothing happens (sorry I can't copy paste from the serial terminal). It has to be a problem with UBoot, as I use the same kernel command line as before and it worked with RedBoot.

Versions of uBoot I tried: 2009/?? (precompiled from denx-cs.de) and latest 2010/06 (compiled myself)

Kernel command line: init=/linuxrc root=ubi0:rootfs rootfstype=ubifs console=ttymxc0,115200 ro panic=1 printk.time=1 ubi.mtd=1

Booting with 

tftpboot 0x80108000 uImage
bootm 0x80108000