Mageia 3 update breaks boot

Hi all,
This is an awkward one to give any details on. I did the online upgrade from 2-3 and after that the machine became unbootable. Not even grub, it would just reset itself immediately after getting past the bios.
I figured the update process was broken, and so I installed from dvd. Got it all working, rebooted in there etc. Everything is happy, then I ran the updates, and the same result.
Is this a known bug? Any ideas what it could be? This is a 64bit asus laptop - I think a K55, but I'd need to check. No other OSes installed. LUKS encryption on individual partitions (not an encrypted LVM partition). Not sure what other details may be useful.
Cheers,
Alan
This is an awkward one to give any details on. I did the online upgrade from 2-3 and after that the machine became unbootable. Not even grub, it would just reset itself immediately after getting past the bios.
I figured the update process was broken, and so I installed from dvd. Got it all working, rebooted in there etc. Everything is happy, then I ran the updates, and the same result.
Is this a known bug? Any ideas what it could be? This is a 64bit asus laptop - I think a K55, but I'd need to check. No other OSes installed. LUKS encryption on individual partitions (not an encrypted LVM partition). Not sure what other details may be useful.
Cheers,
Alan