I've seen similar symptoms (missing devices at boot) go away when I've increased the delay after the call to udevsynthesize in the initrd's init. You can try increasing the argument to sleep in /usr/share/initramfs-tools/init (around line 72):# Populate /dev tree log_begin_msg "Initializing /dev" mkdir /dev/.udevdbUDEVD_EXPECTED_SEQNUM=$(($(cat /sys/kernel/hotplug_seqnum) + 1)) udevd --daemonudevsynthesize sleep 2 log_end_msgTry changing 'sleep 2' to 'sleep 20', regenerate the initrd and reboot. Let us know if it fixes the problem.
I changed it to sleep 10, and up to now, it hasn't occured again. thanks.However, I would ask you not to call that a fix, it's just a quite ugly workaround, something that should not end up in a stable release. And it makes another issue more annoying because the fbcon module is currently loaded after the sleep, so I have for about 12 seconds a blank screen (with vga=791). With sleep 2, it was about 4 seconds, something that was more or less acceptable.
The proper fix is to avoid the race condition, by appropriate locking code in the concerned software.
Willi