Bless Hex Editor only showing ASCII squares

I tried reading the contents of a BIOS EEPROM Chip saved in a file called dump.bin. I also tried opening a file called coreboot.rom containing a Coreboot image. In both cases this error occurred: I used Bless Hexeditor to open the file, but I only got these ASCII squares with four numbers in it, describing which ASCII value the characters have. Most of them are 0046-squares, which equivalents to letter "F". This goes well with what I already know about the contents of dump.bin.

How can I make Bless Hexeditor show me the real byte values as integers/characters? I didn't find any resource regarding this topic. I tried reinstalling Bless with Synaptic package manager, but it didn't help.

I use Ubuntu 20.04.2 LTS, Xubuntu flavor. I use xfce4 desktop but I also have some GNOME stuff installed. ls /usr/bin/*session returns

/usr/bin/dbus-run-session
/usr/bin/gnome-session-custom-session
/usr/bin/gnome-session
/usr/bin/xfce4-session

Edit: When I run bless in terminal, I get the following errors before bless starts:

Could not find a part of the path '/home/user/.config/bless/plugins'.
Could not find a part of the path '/home/user/.config/bless/plugins'.
Could not find file "/home/user/.config/bless/export_patterns"

When searching for these errors, I found this thread saying that the errors don't actually mean sth.

Edit2: I found that GHex works just fine, so I'll probably stick with that. It's weird though that a friend of mine using Bless with Ubuntu 20.04 doesn't have this problem.