Upgrade to Ubuntu 19.04 on HP Elitebook 840 G1 results in blinking cursor after bootloader

Question

I used to dual boot Windows (on dev/sda1) and Ubuntu 18.04, on my HP Elitebook 840 G1 (SSD). I also have a third partition for most of my files (I believe on dev/sda2 named D:/).

I tried upgrading to 18.10, which worked, after which I wanted to upgrade to 19.04. GRUB still finds the boot options I want, but when I try to boot into Ubuntu, I get a blinking cursor (after the ubuntu logo). Also going into "advanced options" in GRUB and selection 4.15.0-55-generic gives me the blinking cursor (after the ubuntu logo).

I wanted to know if anyone had managed to solve this? I have tried:

• booting from a stick with Ubuntu 19.04 (most of the times it doesn't even boot into the stick, and when it does, I also get a flashing underscores)
• boot into recovery mode and change the GPU settings as proposed by heynnema (gdm3 display manager hangs after booting with Ubuntu 18.10)

The fact that even booting from stick gives an error maybe indicates that it indeed is a graphic error?

Answer 1

This is not a proper answer, but I didn't get anywhere. What I tried and failed:

• reinstall GRUB
• reinstall graphics card

I ended up switching back to Ubuntu 18.04 (reinstalled 18.04 from stick onto the partition of the "broken" 19.04). Now I have a GUI. Will wait for 20.04.