Wow, it really stuns me how active the community is, a big plus from my side.
I have 3 partitions created from W10, my efi partition is sda2 with 100MB, all in total taking 180GB on my SSD and one additional created during archlabs install with the rest of the available memory (60GB). The important things are
a) Yes, Windows made the efi partition automatically vfat/fat32, so I doubt that is the problem
b) while at the install step “partition drive”, I was asked to locate the mountpoint for /boot. I used the EFI-Partition that was created by W10, that should be right (right?). Obviously I skipped the formating. I picked this partition because my intuition told me that grub will possibly detect the windows files on there and manage everything on it’s own.
IIRC I ran that command too, post install while desperately trying to fix this issue, but still it didn’t find W10. Also regarding to the multiboot simplicity, on the link I provided the Arch Forum claims that rEFInd as well as systemd-boot are capable of finding the bootmgfw.efi (on their own, altough I didn’t try yet).
I did a fresh W10 install now, because I want to investigate what exactly SHOULD be in the boot partition. When I install archlabs with grub, there is no bootmgfw.efi left, the only thing W10 related is a folder /Microsoft/Recovery/ and inside some backup files if I remember corretly.
Two possible workarounds that popped into my mind could be
a) try systemd and pray that it works
b) create yet another fresh partition and install grub there, and don’t touch the efi partition windows created
c) in the live usb install environment try running os-prober and friends to test if W10 gets detected, and only then proceed the installation
but I don’t know if this will lead to more problems. Furthermore, this seems to me more like a workaround, rather than a fix.
Which leads me to my final question: now I want to install archlabs yet again, what are the procedures for a workaround, to detect W10. Do I have to install archlabs and wipe the windows bootloader again, and then try your workaround? Or should I edit something during install? All in all this seems weird, it is okay for grub to not be able to detect windows at first, I have archlabs on my secondary PC and it didn’t detect it too at first. But wiping the existing .efi file is kind of weird, no wonder that os-prober, update-grub, etc. can’t find a windows bootloader to chainload (because there isn’t one).
Also side note, I loaded the archlabs iso onto my usb stick with Rufus and picked MBR instead of GPT (or how it’s called). But that should not be the problem since my laptop still detects the USB and boots from it.