Monday, 2 May 2016

E2B not booting on GA-73PVM-S2H PC

Samir contacted me about a problem he had with his GA-73PVM-S2H PC.

He could boot from this PC to a USB drive prepared using Rufus (to Elemetary OS, for example), but not if it contained E2B.

The symptom was that the PC would just hang with no keyboard response or boot messages of any kind, as soon as he tried to boot from the E2B USB drive...





The same E2B USB drive would boot under QEMU and on other PCs, just not the GA-73PVM. This pointed to a BIOS problem and he upgraded his BIOS from F7 to F8 but the problem was still present.

After some time experimenting, it turned out that the GA-73PVM BIOS did not seem to like the grub4dos MBR boot code. i.e. the boot chain should be:

grub4dos MBR - sectors 1-20 loaded - grldr loaded -> \menu.lst loaded

If the MBR boot code was replaced by standard 'boot-to-the-active-partition' boot code (by using RMPrepUSB - Ctrl+B) and we already had grub4dos installed to the PBR of the E2B drive (it always is if you use the MAKE_E2B_USB_DRIVE (run as admin).cmd script), then it would boot from the GA-73PVM. i.e.

standard MBR -> grub4dos PBR -> grldr loaded -> \menu.lst loaded - E2B menu

We tried two more (different) versions of grub4dos MBR boot code (by installing to the MBR using Pauly's excellent BootIce tool  - grub4dos 0.4.5c and 0.4.6a options), and they all gave the same problem. I suspected that there was a keyboard/BIOS issue because grub4dos uses keyboard BIOS calls with a timeout in this boot code and other users have said that they do not get a problem if a PS/2 keyboard is used instead of a USB keyboard. As Rufus did not use grub4dos, it did not have the issue.

After doing a Google search, I found that many people who had USB keyboards connected to the GA73-PVM also had similar USB boot problems or 'dead keyboard' problems. Some of them suggested that BIOS version F6 and F4 worked, so Samir tried all BIOS versions from F2 to F9E.

It turned out that BIOS F6 and previous versions worked OK (if you selected the USB device using the USB-HDD+ entry), but all versions after F6 gave the 'hang' issue.