<< Solved >> Inconsistent/flaky BIOS/UEFI behaviour: booting into BIOS instead of EFI

[Tazling]

I've succeeded at last in making my Hackintosh dual-OS, with WinDoze 10 on one internal SSD and Mojave on another; the Win10 side has been up and running over 24 hours, installed some games, ran virus checks, did some personalising... now it's time to shut'er down and go back to Mojave-land. And now I'm facing a new problem. It's quite maddening.

The mobo is ASUS MAXIMUS XI HERO. The symptom is that when I reboot, no matter what UEFI volume I choose as #1 in the list of boot devices, the mobo always boots back into BIOS. What I see in the menu is 2 (?) UEFI boot devices associated with SSD number 1 (MacOS), 1 Microsoft Windows EFI boot associated with SSD number 2, Win10, and 1 bogus EFI device associated for some reason with one of my SATA drives.

The default boot device keeps reverting to Microsoft Windows EFI Boot (SSD 2). Also, the boot device list keeps reverting to empty, with the Microsoft EFI Boot listed as "Override." When I use F8 to invoke the boot menu, SSD 1 does not appear; only Microsoft Windows EFI appears. When I go into BIOS and visit the Boot configuration screen, the four options described above appear but don't seem to do anything.

I have (not sure how) at least once overcome this by sheer stubbornness: booting over and over again, disconnecting AC from the power supply, etc. But this afternoon I really got stuck. Booted about 12 times into BIOS, power cycled at least 2 times, before I gave up and plugged in my Mojave rescue USB stick. Ta-da! instant boot into Mojave. No pause in Clover, though!

So... what is to be done? I found some gripes online, two or three years old, about Asus mobos misbehaving and booting into BIOS... but no real answers. Some suggest memory could be at fault; I will run a memory diagnostic, but it seems unlikely I have bad RAM given the successful run-time of Windows and a few demanding game apps over the last 24 hours.

I carefully disabled Windows auto-update (first thing I did after booting it, just about) so this should not be a matter of WinDope whimsically reinstalling bits of itself and clobbering my EFI partition... but I'll check.

If anyone has thoughts on the cause of a mobo booting repeatedly into BIOS and ignoring the EFI partitions available to it, I'm all ears.

 

[Tazling]

The more I work on this problem the less I think it's the mobo or the BIOS at fault. I think something has gone wrong with my UEFI and I can't figure out when, how or why.

Basically, yesterday I could boot to Clover and then Mojave, then I could boot to Clover after shutting down Mojave, select Win10 boot disk and boot Win10. Everything seemed to be working! I left Win10 up overnight and most of today. Thought this whole UEFI war was over. But I guess that was just one successful dual boot cycle...

Anyway, I thought I'd shut down and boot into Mojave again, and that's when the madness began. Booting to BIOS every time. Like BIOS no longer recognised any volume as bootable.

I can see my Mojave SSD and the Win10 SSD in the BIOS boot menu, but selecting them changes nothing: still boot into BIOS on every attempt.

However.... if I plug in my original Mojave rescue USB stick, I can get to Mojave (but alas, with no pause in Clover so no chance to try booting Win10).

If I plug in my "rescue" USB external SSD (CCC of my Mojave boot disk about a week old), wow, I can get to Clover and it shows all the possible boot options -- boot Mojave from rescue SSD, boot Mojave from internal SSD, and one icon with Windows logo in it which looks hopeful. If I unplug it and try again, back to BIOS boot nightmare. With rescue disk: everything looks pretty good. Without rescue disk: still broken.

So I thought, OK, the EFI folder on the rescue USB SSD works, whereas the one on the internal SSD does not work. So if I replace the broken one with the working one, I should repair my problem, no? So I saved and then deleted the EFI folder on the internal Mojave boot disk. I installed Clover all over again to internal boot disk. Then copied the EFI folder from the rescue USB SSD to the internal boot disk.

Tried another boot. Yes, it worked... But the list of bootable disks was suddenly shorter. Only the Mojave boot disk was there, plus the usual Recovery and EFI icons. No Microsoft boot. So it's nice that I can boot Mojave from the internal disk once more, but now I've lost my Win10 boot option. This is like one of those vintage comedy routines where the guy picks up three things and drops two and so on.

So I carefully re-read writeups here and elsewhere, and looked hard at my EFI partition. I have read in some places "rename your bootmgfw.efi to bootmgfw-orig.efi" like that's all that's needed -- and in other places (like here in an El Cap writeup) that you also have to copy CLOVERx64.efi as a new bootmgfw.efi to replace the one you renamed. So I tried that. It certainly changed the behaviour

What happens now seems encouraging at first. I get to Clover. F3 reveals a whole row of boot disk icons. One of them has a Windows logo on it. I click on it and... oh dear. I'm in the Clover boot screen again, but it's different. There are only two icons now, and both of them have Windows logos. And if I click on one, I end up at the Clover boot screen with just one Windows icon... and if I click on that, rinse, repeat. So I'm almost there... except that I can't get a Windows boot started. I just loop around in Clover forever.

What I'm really not understanding right now is whether there is only one EFI partition in play (the one on my internal disk) or two (one on the disk where I installed Win10). diskutil list doesn't show me an EFI partition on the Win10 boot disk. It shows only a teeny little 17MB partition and then the rest of the disk as one chunk. of course I can't mount it or inspect it 'cos it is NTFS.

My suspicion is that Windows, just by booting or running for a while, did something to the (one) EFI partition that everyone is using to boot from. Whatever it did mucked up the EFI folder so that the BIOS thought there was nothing bootable out there. My attempts to repair the damage have been ignorant, so I haven't really got it right yet: I think it's got something to do with the relationship between those MS bootmgfw files and the clover boot files. Help? Advice?

[update:] When I installed Win10, I know there was an EFI partition on its disk. I saw it. Now there isn't one. All that happened in between was that Win10 booted and ran for a while. Googling around, I find alarming reports of Win10 deleting its own EFI partition, with complicated recipes for repairing the damage. Could that be what has happened here?

 

[Tazling]

Solved, here's the answer

<< Solved >> - UEFI Hell... some specific questions

Back again after another tedious win10 install. Here's what seems (right now) to have worked (magically!) for me. A reminder: 2 internal SSDs. Mojave is on the M.2 NVME SSD on the mobo. The Win10 target is an SSD in a PCIe adapter in slot 3. ASUS MAXIMUS XI HERO. SSDs cannot be disabled...

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