Same problem with Ubuntu 20.04 on a ThinkPad X1 Carbon 4th.
"apt-get upgrade" froze at the installing the intel-ucode update. Then it also refused to start. As a workaround, I followed similar steps Paulo:
* Booting into recovery mode
* Step 1: dpkg --configure -a
* Step 2: apt --purge remove intel-microcode (first, I had to restore networking, but continuing boot in normal mode)
I also realized that the /boot partition was out of space. So, I also had to run "apt-get auto-remove" first.
Same problem with Ubuntu 20.04 on a ThinkPad X1 Carbon 4th.
"apt-get upgrade" froze at the installing the intel-ucode update. Then it also refused to start. As a workaround, I followed similar steps Paulo:
* Booting into recovery mode
* Step 1: dpkg --configure -a
* Step 2: apt --purge remove intel-microcode (first, I had to restore networking, but continuing boot in normal mode)
I also realized that the /boot partition was out of space. So, I also had to run "apt-get auto-remove" first.