Black screen on Lubuntu

Question

I've got a fresh install of Lubuntu 16.04 with dual boot. It worked well the first few times I started it but it doesn t work anymore. I get a black screen after selecting the default choice in GRUB. However, if I launch recovery mode, and choose "resume" I get a low definition but otherwise perfect start. Reinstalling Lubuntu soon leads to the same problem, as I tried a few times. I believe some driver in it isn t appropriate or crashes. From a live USB stick, I get full resolution without any problem. Thinking it could be related to the display manager, I installed gdm3 and made it default but it doesn't work either. What should I do ? The laptop is a Toshiba Satellite with "AMD A6-3420M APU with Radeon HD graphics" EDIT : For some reason, launching with "resume" from recovery doesn't work anymore. I get the login prompt for tty1 on a blinking screen instead.

Answer 1

[If this doesn't work, I'll remove it]

If it does, then it'll be a dupe FYI.

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At GRUB boot to recovery mode and drop to a root shell.

1) Mount the file system as R/W: mount -o remount,rw /

2) Next, run sudo nano /etc/default/grub

3) Then add nomodeset to GRUB_CMDLINE_LINUX_DEFAULT:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

Becomes:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"

And then save by hitting Ctrl+O, then exit nano with Ctrl+X

4) Finally, run:

sudo update-grub
sudo reboot