Hi Paul, Thanks. I should have said, that also apt-get autoremove fails:
$ sudo apt-get autoremove Reading package lists... Done Building dependency tree... Done Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Setting up initramfs-tools (0.139ubuntu3) ... update-initramfs: deferring update (trigger activated) Processing triggers for initramfs-tools (0.139ubuntu3) ... update-initramfs: Generating /boot/initrd.img-5.11.0-25-generic Error 24 : Write error : cannot write compressed block E: mkinitramfs failure cpio 141 lz4 -9 -l 24 update-initramfs: failed for /boot/initrd.img-5.11.0-25-generic with 1. dpkg: error processing package initramfs-tools (--configure): installed initramfs-tools package post-installation script subprocess returned error exit status 1 Errors were encountered while processing: initramfs-tools E: Sub-process /usr/bin/dpkg returned an error code (1) Maybe this is a bug in the dpkg? This sounds like some disk (it's a few years old SSD) error, but I don't know: "Error 24 : Write error : cannot write compressed block" Contents of the /boot: total 343M -rw-r--r-- 1 root root 248K kesä 17 01:38 config-5.11.0-22-generic -rw-r--r-- 1 root root 248K heinä 9 20:42 config-5.11.0-25-generic drwx------ 6 root root 4,0K tammi 1 1970 efi drwxr-xr-x 4 root root 4,0K heinä 23 13:13 grub -rw-r--r-- 1 root root 153M heinä 10 14:22 initrd.img-5.11.0-22-generic -rw-r--r-- 1 root root 151M heinä 23 13:13 initrd.img-5.11.0-25-generic lrwxrwxrwx 1 root root 28 heinä 23 06:04 initrd.img.old -> initrd.img-5.11.0-22-generic drwx------ 2 root root 16K heinä 6 08:52 lost+found -rw-r--r-- 1 root root 179K elo 18 2020 memtest86+.bin -rw-r--r-- 1 root root 181K elo 18 2020 memtest86+.elf -rw-r--r-- 1 root root 181K elo 18 2020 memtest86+_multiboot.bin -rw------- 1 root root 5,7M kesä 17 01:38 System.map-5.11.0-22-generic -rw------- 1 root root 5,7M heinä 9 20:42 System.map-5.11.0-25-generic lrwxrwxrwx 1 root root 25 heinä 23 06:04 vmlinuz -> vmlinuz-5.11.0-25-generic -rw------- 1 root root 15M kesä 17 01:55 vmlinuz-5.11.0-22-generic -rw------- 1 root root 15M heinä 9 21:04 vmlinuz-5.11.0-25-generic lrwxrwxrwx 1 root root 25 heinä 23 06:04 vmlinuz.old -> vmlinuz-5.11.0-22-generic Ilkka