Weird messages when running update-grub command. Is the HDD/SSD intact?

Question

Debian

Hello. Usually, I connect to a PC router with Debian Jessie on board via SSH. Today I decided to tweak the /etc/default/grub. When executing the update-grub command over SSH, nothing criminal is output to the console, while on the monitor screen in the TTY, when executing update-grub, the following is displayed:

[   57.029287] EXT4-fs (sda2): unable to read superblock
[   57.033730] EXT4-fs (sda2): unable to read superblock
[   57.038082] EXT4-fs (sda2): unable to read superblock
[   57.058510] FAT-fs (sda2): bogus number of reserved sectors
[   57.063072] FAT-fs (sda2): bogus number of reserved sectors
[   57.086264] qnx4: no qnx4 filesystem (no root dir).
[   57.434131] EXT4-fs (sdb2): unable to read superblock
[   57.438641] EXT4-fs (sdb2): unable to read superblock
[   57.443198] EXT4-fs (sdb2): unable to read superblock
[   57.464281] FAT-fs (sdb2): invalid media value (0xde)
[   57.469226] FAT-fs (sdb2): invalid media value (0xde)
[   57.489591] qnx4: no qnx4 filesystem (no root dir).

Judging by the inscriptions, there is a problem with hard drives. In this case, sda2 is an SSD and sdb2 is a normal HDD. Tell me, please, is there really a problem with the disks or is it a bug in update-grub? When the system boots, there are no such inscriptions - only when updating-grub is executed.
Sincerely.

Answer 1

What kind of filesystems are actually on partitions? Or maybe there is LVM or something else interesting?
You almost certainly have the os-prober package installed. It is called during update-grub and searches all block devices for loaders of other operating systems. To do this, it pulls the drivers of different file systems, and they, in turn, complain to dmesg that they do not see such a file system on this partition.