Restart hangs, but USB boot only after restart

My AAO 150L (still on Linpus) doesn't boot from USB on startup. After pressing F12 only the HDD shows up in the BIOs menu. I've tried various sticks and CDROMs. I have to boot to the GUI, then do a restart (not shutdown!). If I press F12 then, the USB drive shows up and I can boot form there. At least that's how it has been working when I did backups with TrueImage and experimented with installing Ubuntu and Fedora. But now restart doesn't work anymore. The default Linpus application menu disappears, the search bar is still visible and then nothing happens. It just hangs. I have to push the power button, then it shuts down. But when I turn it on again, I can't boot from USB, see above :? . So now I can't even restore the backup, because I can't boot TrueImage. Shutdown still works as it should, only restart hangs

Any ideas how I get restart working again? Or how to be able to boot from USB on the first startup after switching the AAO on? My BIOS version is 0.3309

 

Sounds like a defective machine. Pretty much the only way this can happen is if the BIOS isn't initializing the USB subsystem.

I would try reflashing the BIOS, and if this doesn't work, return the unit for service.

 

Thanks, I'll maybe try reflashing the BIOS later. I have found another way to boot from USB: On startup I enter the BIOS menu (F2) then say "save and exit" F10 and when it reboots I open the boot menu (F12) and my CDROM shows up. That way I was able to install Fedora and now, of course, restart works again