I have installed squeeze on a pen drive with separate /boot partition and /root on lvm.
@initramfs busybox shell "lvm lvscan -a --ignorelockingfailure" does not work unless "lvm vgscan --ignorelockingfailure" is executed prior to it. I applied the patch from http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=10;filename=lvm2_wait-lvm.patch;att=1;bug=568838but get infinite messages "no volume group found" I modified the script to include "lvm vgscan --ignorelockingfailure" before the loop and it worked. Hope this helps. I am a linux newbee.