RL85 BIOS Boot Menu Disappeared

I've found what the issue was and its my lack of experience/understanding of how the uefi bios works. If using an OS that does not provide a uefi aware boot manager/OS then bios boot menu will appear and function as expected. If using an OS that is aware like Win8/10 then the boot menu disappears and the f12/del keys won't work. To access the bios setting and select a boot device you first have to boot into Win10 (in my case) and then press the shift key whilst selecting restart and the options will be there or you may have to drill down a few advanced menus. I'm not sure if there are any other key presses you can make on boot to be presented with the same options or not. Also if you remove the disk with the uefi aware OS then the standard boot menu will reappear and function as expected. 

I guess there are benefits to better bios integration and management with the OS although without any information on this being displayed to the user it relies on google a bit too much. 

More info here -> http://www.howtogeek.com/175649/what-you-need-to-know-about-using-uefi-instead-of-the-bios/

Hi,

Interesting scenario. Am I correct to assume you have CSM disabled in the BIOS? Also what have you set as the boot order / priority as in theory (as in the nice logical traditional way) then you should be able to set the usb device to have priority over the disks, or in this case Windows Boot Manager. However it might be the case that Windows Boot Manager just takes over everything.

In my set up where I was trying to dual boot with Linux Mint on the same disk, I had to revert to enabling CSM in the BIOS which then allowed for legacy MBR type booting, over GPT partitions. I then reinstalled Windows 10 and upon trying to install Linux Mint it wouldn't see the Windows 10 partitions on the disk (in gparted / mint installer), just showing an empty disk. This was due to some GPT rubbish still being left around for which I found a linux command you can run to clear this out. It then was able to install Mint and grub was then the boot loader which allowed booting into mint or windows. I did end up with a slight bug in that sometimes booting would hang with a line at the bottom of the dell screen I was using (with a hdmi to dvi cable). However it might just be the dell screen crashing rather than an issue with the acer itself or a combination of the two

I think this was the command I used to remove the gpt information- 

# sgdisk --zap /dev/sdc

Where c is the disk you are trying to remove it from. I must have used the lowercase -z or --zap as my MBR remained intact and Windows was still able to boot at that point. 

Warning: Be sure to use a lowercase -z if you want to keep the MBR! If you use an uppercase -Z (--zap-all), the MBR will be erased, as well as the GPT! This is useful if you want to create a fresh MBR with another utility or if you want to use the disk with another partitioning system entirely.

Hi, glad you have it working. I think when you enable CSM then the current UEFI / GPT Windows install needs to be modified in some way in order to boot although I'm not exactly sure what can do that. I just reinstalled Windows 10 once CSM was enabled and it appeared to perform an MBR based install. 

My other frustations with this set up was that I orginally upgraded the default win8 install to win10 but then wanted to perform a clean install on a newly installed ssd in the 2nd bay. This worked except it used the windows boot manager on the first disk which I didn't want. I then removed all the partitions from the default first disk and promptly had to reinstall win10 again on the second disk. I then ran into the UEFI/GPT dual boot issues with Linux Mint and following enabling CSM I then ran into another issue where Windows 10 won't install as an MBR boot on a second disk. So I have to swap the default and SSD disks around to get that to work. I then fixed the left over GPT partition information on the disks as described above.

What a faff!