Grub2 install fails on USB drive with error: appears to contain a ufs1 filesystem

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Published on September 28th 2018 - Listed in Linux


In my previous article (How to compare speed of USB flash pen drives) I briefly mentioned I had to reinstall the OS of my NAS-server on a USB flash drive. When I did so, the last step in the Debian installer (install grub2) failed, but without a clear error message. Because I was in a hurry back then, I installed LILO as bootloader. This worked and the NAS booted correctly.

Now it was time to investigate and on the running Debian OS I tried to install grub2:

root@nas:~# apt-get install grub2
Reading package lists... Done
Building dependency tree      
Reading state information... Done
The following NEW packages will be installed:
  grub2
0 upgraded, 1 newly installed, 0 to remove and 6 not upgraded.
Need to get 2,476 B of archives.
After this operation, 16.4 kB of additional disk space will be used.
Get:1 http://ftp.ch.debian.org/debian stretch/main amd64 grub2 amd64 2.02~beta3-5 [2,476 B]
Fetched 2,476 B in 0s (38.7 kB/s)
Selecting previously unselected package grub2.
(Reading database ... 28456 files and directories currently installed.)
Preparing to unpack .../grub2_2.02~beta3-5_amd64.deb ...
Unpacking grub2 (2.02~beta3-5) ...
Setting up grub2 (2.02~beta3-5) ...

So the installation of the package itself worked. What about the grub install?

root@nas:~# grub-install /dev/sde
Installing for i386-pc platform.
grub-install: error: hostdisk//dev/sde appears to contain a ufs1 filesystem which isn't known to reserve space for DOS-style boot.  Installing GRUB there could result in FILESYSTEM DESTRUCTION if valuable data is overwritten by grub-setup (--skip-fs-probe disables this check, use at your own risk).

When I was searching for this error I came across a Linux mint bug (grub-install fails on drive that previously had ufs2 installed). This is a true fact for the USB drive I'm using in the NAS server, it was previously used as a simple USB pen drive. So I tried to use the --skip-fs-probe parameter:

root@nas:~# grub-install /dev/sde --skip-fs-probe
Installing for i386-pc platform.
grub-install: warning: Attempting to install GRUB to a disk with multiple partition labels.  This is not supported yet..
grub-install: warning: Embedding is not possible.  GRUB can only be installed in this setup by using blocklists.  However, blocklists are UNRELIABLE and their use is discouraged..
grub-install: error: will not proceed with blocklists.

Now I was at the same point as in the mentioned bug report.

I decided to wipe the first 2047 sectors of the flash drive:

root@nas:~# dd if=/dev/zero of=/dev/sde bs=512 seek=1 count=2047
2047+0 records in
2047+0 records out
1048064 bytes (1.0 MB, 1.0 MiB) copied, 0.111457 s, 9.4 MB/s

Now there shouldn't be anything left to cause a grub-install hiccup. Let's try it again:

root@nas:~# grub-install /dev/sde
Installing for i386-pc platform.
Installation finished. No error reported.

Hurray! Oh and wow, the NAS boots so much faster with grub2 than with ILO (haven't used ILO since 2005...)


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