Trying to UEFI boot from USB flash drive

[MikeK]

I'm trying to setup my laptop with a dual boot.  It already has Win10, but I want to add Linux Mint.

I used balenaEtcher to setup an SD card with Mint21.  The SD card is in a USB SD card reader.  I can get the laptop to do a legacy boot from the USB drive, but I need a UEFI boot from it in order to setup the dual boot.  If I do the legacy boot, the installer doesn't give me the option to "install Linux alongside Windows".  And I don't know why this isn't working.  I have spent all day on this, redoing the flash drive and retrying the boot.

I managed to get a UEFI USB drive boot option *one time*.  But I shutdown the computer without doing the install and now I can't get that option again.  I have changed *nothing* in BIOS.

Can anyone shed some light on this?

[MikeK]

I figured it out, but it's weird.  I went into boot option, just moved around, not changing anything, then escaped.  When it restarted (with the USB drive plugged in) the UEFI USB drive option was there.  And I now remember this is that I did last time.  That is some weird shit.  I didn't make any changes at all.

[David Hess]

On my own systems the BIOS gives options depending on what drives are enumerated, so making a change requires going through POST again.

[DiTBho]

That is some weird shit

PC BIOSes are like that. Weird shit.

I had a similar problem on my x86 laptop, I had to give up and move GNU/Linux and Haiku on the same hard drive with Windows installed as the first OS.

Thank god "Grub" can boot both kinds, Windows, and *NIX.

[Infraviolet]

Mint's live installer might behave a bit oddly if you have not turned off "secure"boot. It does often manage to boot even with the horrors of secureboot enabled, but then when you try to install from it it gives some rather strange options.

With every computer I've used you set whether to use UEFI vs Legacy BIOS in the BIOS/UEFI settings, then it will detect any bootable devices and try to boot from them in whichever mode UEFI/Legacy you have told the computer to use. Live installers USBs usually have the capability to boot from whichever mode the PC is working in. The devices listed, for purposes of setting boot order, may change when you plug in or unplug bootable devices, and the changing between UEFI and Legacy may change those lists too, but I've never seen the devces listed explicitly as being for UEFI vs Legacy mode.

[MikeK]

It had nothing to do with Mint.  I was trying to boot from the USB drive.  It was a BIOS/UEFI "problem".

The machine was/is set to use UEFI boot mode, and then in the boot "listing" it shows options for legacy and options for UEFI.  The USB drive was only showing up under legacy, which wasn't what I needed.  Just going into the Boot Options and moving around - not changing anything - the subsequent restart showed the USB drive under UEFI instead of legacy.

Maybe I don't have things configured correctly, as I don't know much about this.  I guess I could make a short video of it, but yesterday I got it booted properly and Mint21 installed alongside my Win10 so I'm pleased.  I'm sure next time I'll forget what I did.