Hello all,
just FYI, I have the same issue. I bought new bigger SD card "SanDisk SDHC 32GB Ultra Class 10" and wanted to replace old one "ADATA SDHC 16GB Class 10 Turbo". On the old one ADATA I have Archlinux fully updated and works without any problem:
# vcgencmd version
Jan 9 2013 17:27:35
Copyright (c) 2012 Broadcom
version 361556 (release)
# uname -a
Linux pelikan 3.6.11-3-ARCH+ #1 PREEMPT Thu Jan 10 03:05:04 UTC 2013 armv6l GNU/Linux
When I copied the system to the new one SanDisk Raspberry didn't boot. Then I tried to put latest 2012-12-16-wheezy-raspbian and worked fine, then I put archlinux-hf-2012-09-18 and also worked fine, BUT when I did a update pacman -Syu with the latest firmware and kernel it won't boot. So this issue is for sure linked with hardware SanDisk as my ADATA working without any problem.
I will try when there will be a new firmware, hope it will work.