'Critical Error' after attempting to boot EFI in debian

[mattcatt]

hi folks.
I'm trying to run debian through a windows 10 host (x64,8GB RAM) on VB 5.0.10, and for the first reboot it seems to work fine. But every instance after that I am shown the EFI shell. I don't know a great deal about it, so I exited, and found myself in some bootloader I'm not familiar with here -> imgurDOTcom/8ZARUfp. I tried booting from Boot Maintenance Manager/Boot From File/NO VOLUME LABEL,.../EFI/debian/grubx64.efi and got a dialogue box from "VirtualBox - Guru Meditation" that a critical error had occurred and execution had to be halted. Up until that point, here -> pastebinDOTcom/Tfr3m6Qm is my log file.

I've also tried booting from Boot Manager/EFI Hard Disk but it just flashed the screen and returned me to the
main menu shown in the picture. Rearranging my boot order under Boot Maintenance Order/Boot Options had no
effect either.

[Perryg]

Why are you trying to use EFI on a guest? It's not needed and unless you really understand EFI really well will cause you problems.

[mattcatt]

Up to this point, I've installed all my os with EFI enabled and have never run into any problems until now. I'm using debian as a host for experimenting with LFS, which I'd like to implement EFI on for its performance/secure-boot. I wasn't certain if this could be done had the host had not been configured for it, so I figured it'd be a safe bet.

[Perryg]

Well the screen you are seeing is due to the issue I mentioned. You need to point to the proper boot file. Usually it is easier to create a startup.nsh file to do this and then you don't get this boot screen.
The easiest way to create the startup.nsh file is to use the edit feature in the EFI ">" screen.

[mattcatt]

Success! Thank you kindly for the help!