I set up a dual boot windows 10, ubuntu 18.4.3 recently, all worked well.
Out of curiosity I clicked the "system setup" option in grub loader and it took me to the bios -- cool.
But now it will only take me to the bios! even on restart. In an atempt to troubleshoot I tried connecting the same usb that I intially used to boot up ubuntu and install it. But now UEFI doesn't recognize the usb, and in legacy mode I see the usb name but nothing changes b/c it always boots to the bios. (UEFI/GPT usb btw, FAT32 made with rufus). BTW I have tried both enabling and disabling secure boot and even reset bios settings to default. No good.
I'm not sure how, but simply clicking "system setup" in grub loader has changed something vital.
Prehaps grub loader is working but it goes straight to system setup right away and everytime? Possibly a bug with grub loader?