Author Topic: Please need help!- can't boot into UEFI-BIOS- now sporadic black screen on boot  (Read 659 times)

eco_bach

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Hi
Any troubleshooting steps welcome! I have an Asus X99-II mobo and 64 GB RAM. Also 2 SSD's
1- Samsung 950 Pro M.2 SSD with Windows 10
2- Samsung EVO 1TB SSD with Linux (Ubuntu) installed

My setup was working fine for a couple months now. I normally switch between the OS's thru my UEFI on bootup.

I first started encountering issues after an install of some graphics utilities in Ubuntu which resulted in Black screen with flashing cursor on boot.
I could still easilly access my UEFI-BIOS on boot to switch to my Windows install without issue.

Most linux troubleshooting posts pointed to issues with my Grub install so I tried reinstalling Grub using Boot-Repair from a Live USB.
Boot Repair also warned me about my root partition being almost full so I decided I would also need to repartition-reformat my Linux SSD.

I could still enter UEFI BIOS at that point and made a change I think to CMS(Legacy or BIOS boot), changing it to auto

After reinstalling Ubuntu-mate on my Linux SSD, I rebooted but it still would not boot in to my Grub menu. Just a blinking cursor on black screen.
So I ran boot-repair once more and for some reason did not recognize my ESP on my Linux SSD.

So I then booted into Windows and attempted rebooting into UEFI-BIO thru Advanced Startup settings like I normally do.
After restarting my screen pauses for about 10 seconds like its trying to enter UEFI-BIOS then loads Windows.

Ok, so now I can't boot into UEFI but still boot Windows fine
I recall having this issue before and was able to recover by clearing RTC RAM for my Asus mobo. Some confusion though over which actual pins should be shorted to accomplish this ( picture from actual manual)
https://www.manualslib.com/manual/1172800/Asus-X99-A-Ii.html?page=28
This had no effect.
So I then attempted a startup repair, again thru Advanced startup, but after rebooting things became worse....no apparent video signal, just a black screen! WTF!
 So I rebooted again with Shift key held down and was able to get a proper video signal
So not booting into UEFI I think is a symptom of a larger issue and is somehow connected with the black screens I am getting, but now I need some serious troubleshooting steps before I make things worse!

« Last Edit: January 07, 2017, 09:16:15 AM by eco_bach »

Ari Altman

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Honestly, I don't work with Linux installs, and I'm guessing this could have something to do with your dual-boot system. My only recommendation would be to pull both drives entirely out of your system, remove the CMOS battery from the motherboard to clear settings (honestly easier than messing with pins), resinstall it, and attempt to access the UEFI. At that point, it should be returned to factory settings and should be able to enter the UEFI.

eco_bach

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Thanks Ari
Was able to rest my BIOS firmware using the USB BIOS Flashback button on my mobo with downloaded BIOS onto a FAT32 formatted USB. Though had to make an educated guess as to what to rename the .cap file to first for it to work!

I know I need to disable Fast Boot in UEFI  for Linux installs, but the CSM(Legacy mode) and Secure Boot settings(default is enabled) leave me scratching my head. Some guides suggest to disable CSM and use 'UEFI only' but I alwasy seem to encounter issues. Ditto for secure boot if I disable.

Ari Altman

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Remember that CSM stands for Compatibility Support Module. It's best to enable it if you're having trouble booting.

Glad you found a way to reset the BIOS, although pulling the CMOS battery would have the same effect.