Re: EFI boot partition overwritten: mount -t msdosfs (or mount_msdosfs(8))

From: Thomas Laus <>
Date: Sun, 18 Jul 2021 23:50:13 UTC
On 7/18/21 2:21 PM, Graham Perrin wrote:
> On 16/07/2021 18:35, Warner Losh wrote:
>> # newfs_msdos -F 32 /dev/ada0p4
>> # mount -t msdos /dev/ada0p4 /boot/efi
> Typo: msdosfs, not msdos.
> Alternatively, mount_msdosfs(8).
> Alternatively (I agree, even better), incorporate things such as this in
> the Handbook :-)
> Then have the (ahem) book of answers to frequently asked questions link
> to the Handbook.
I agree with having this information in the Handbook.  Writing the
contents of the EFI partition has changed filenames through the recent
release cycles.  FreeBSD 12.0 + uses "dd(1) the /boot/boot1.efifat
file".  FreeBSD 13.0 has a gptboot.efi in the /boot directory I was
tempted to use 'gpart bootcode -p /boot/gptboot.efi' like writing the
boot record on a ZFS system but was concerned about digging a bigger
hole.  Warner Losh has still another way of writing the EFI partition
contents.  Once the Handbook defines a 'standard' method, the
/usr/src/UPDATING file can just reference it.


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