Arch Linux

theta112358

Member

Registered: 2021-06-24

Posts: 1

During Setup: possible mistake with fdisk, now / is write-protected

Hi,

I'm a complete newbie to setting up Arch filesystems, so I've been following the Installation wiki page. I've already used fdisk to partition my drive, set the filetype of /dev/sda2 to ext4, set /dev/sda4 as swap and "swapped on," and finally mounted /dev/sda2. After using chroot to select /dev/sda2 as my root directory, everything was fine for a while. I was able to change timezone settings, edit some network config files, and create a new root password, all of which involve writing info to the disk.

Then I discovered that I do indeed need to set up an EFI partition for UEFI boot, something I'd neglected to do when I initially partitioned the disk. (I'm using GRUB and I'm still not sure exactly how the UEFI partition works.) Since I'm switching this laptop from Windows to Linux, it already had a 500 MiB boot sector that I hadn't touched (was this already what I needed?). I figured I'd change the type to ef (EFI FAT-12/16/32) *with everything still mounted,* ignoring some warnings -- which may have been a mistake, because now, /dev/sda2 is write-protected. Is there any way to turn this write-protection off? Or did I do something weird enough that I should scrap everything, boot up from the .iso file again, and repartition the drive?

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,331

Re: During Setup: possible mistake with fdisk, now / is write-protected

These are all very vague descriptions, check your history and post the actual commands you issued. Have you already tried just unmounting and remounting the / partition after exiting the chroot? Are there any error messages on doing so from the mount process/in dmesg?

That said a Windows allocated EFI partition normally already has the type EFI fat (... that designation is what the UEFI would use to identify the partition to boot from) and normally is around 100MB in size rather than 500MB so you likely didn't really adjust the correct thing and if you do not have an ESP in the first place it's likely you aren't even booting in UEFI mode (.... did you do the relevant checks in https://wiki.archlinux.org/title/Instal … _boot_mode  ?)

Mr Victory

Member

Registered: 2021-06-10

Posts: 41

Re: During Setup: possible mistake with fdisk, now / is write-protected

I figured I'd change the type to ef (EFI FAT-12/16/32)

Partition types of 2 characters indicate you are using MBR and you are trying to create an UEFI/MBR setup. UEFI is intended to be used with GPT partition table.

Or did I do something weird enough that I should scrap everything, boot up from the .iso file again, and repartition the drive

If you are going to erase windows, I recommend you to delete first all of the partitions, then the MBR and take your time to choose between MBR/BIOS and GPT/UEFI. When you decide, ensure you are booting in the desired mode.

did you do the relevant checks in https://wiki.archlinux.org/title/Instal … _boot_mode?)