Strange Recurring UEFI Boot Issue

[webplus]

Something else I've noticed. When it does boot directly from the Mac SSD it won't fail to boot until the computer has been powered off either at the mains or via the on/off switch on the back of the case.

A while ago it was booting from the SSD fine. I shut the computer down and switched it off so that no power was going to the computer. When it then repeatedly failed to boot, I used the USB installer to boot. I removed the USB and rebooted and I can boot directly from the SSD again.

Something seems to be cleared or deleted when there's no power going to the computer?

 

[84mac]

Something else I've noticed. When it does boot directly from the Mac SSD it won't fail to boot until the computer has been powered off either at the mains or via the on/off switch on the back of the case.

A while ago it was booting from the SSD fine. I shut the computer down and switched it off so that no power was going to the computer. When it then repeatedly failed to boot, I used the USB installer to boot. I removed the USB and rebooted and I can boot directly from the SSD again.

Something seems to be cleared or deleted when there's no power going to the computer?

WARNING - don't do anything based upon my observations here until you do some serious investigation or someone else speaks up - and aside from knowing for sure you have your board's latest firmware rev ... BUT - your issue really feels/smells like a reset of uefi/bios/cmos may be in the solution pile after exhausting firmware/chipset issues...

that said, my hacks are on series7 boards and different brand (gigabyte), but everyday I deal with lots of hardware/firmware and chipset issues on (asus) and many other brands, negotiating multiple operating systems...

just to ask, have you checked tweaktown for modified and/or more current firmware loads?... they do tend to pick up the slack after the mfgs have moved on to newer/other pcb builds...again - all speculating, but not without some real-world low-level hardware experience... ymmv...