Boot from GPT system disk not working

[lellis1936]

I recently converted my system disk (which also already was using SEDUTIL) to GPT using mbr2gpt. Everything went well.

After that I installed the UEFI64 PBA image (I had been previous using the lean BIOS PBA). The UEFI boot of the PBA environment worked fine. But the chainloading of my Windows OS did not. The following sequence of messages occurred:

About to Chainload hd0,0 Booting...

Reboot and Select proper Boot device
or Insert Boot Media in selected Boot device and press a key

If, at this point, I press a key, the cursor drops down a line, continues to blink, but nothing else happens. If instead I use CTRL-ALT-DELETE, the reboot occurs, and the OS loads fine.

Any ideas about if, and how, I can get this working?

[lellis1936]

I justed wanted to add that, since this OS drive was converted to GPT after OS installation, the EFI system partition is not in the ususal postiion (first partition) of the drive. It is the third partition of the drive.

I don't know how chainloading works but it makes me wonder if hd0,0 is correct, and whether and how I can change that.

EDIT I reordered the partitions using Macrium Reflect so that the EFI partition is first. That did not solve my problem, though, so other ideas are welcome.

[lellis1936]

I discovered the answer to this dilemma on my own through experimentation.

What was happening is that my BIOS (which is quite old), was doing an MBR boot of the PBA, not a UEFI one. My BIOS requires a UEFI boot menu option to exist in most boot scenarios. There wasn't one for the PBA environment, so the MBR boot was used.

I used EasyUEFI bootable to add a UEFI boot item for the SEDUTIL UEFI PBA. After that, the system boots in UEFI mode as it should. It does do a BIOS post after the disks are unlocked, so in my scenario it's not a huge improvement over the MBR flavor, although it IS nice not to have to use the three-finger CTRL-ALT-DEL sequence.

EDIT: There is a frequent problem that when the UEFI PBA prompts for a password, no input is accepted from the keyboard. Resetting or power cycling the computer fixes this, but sometime several attempts are required. This nuisance makes the MBR PBA (which does not suffer from this problem) preferable for me.