For more than a year I have used Ubuntu 18.04 LTS in dual boot with Windows 10 on my laptop Asus Zenbook UX305CA, without any problems.
Suddenly, some weeks ago, out of the blue, an attempt to boot Ubuntu freezes the screen, leaving it black whiteout any ways to contact the system. Windows was bootable as usual.
To get in contact with Ubuntu I had to use "Ubuntu, with Linux 4.15.0-123 (generic recovery mode)", from grub's boot menu. This gave me Ubuntu in a miserable resolution. Attempt to restart freezes the screen like before.
I then decided to upgrade to Ubuntu 20.04 LTS hoping to get rid of problems that way.
The situation is now, that Windows is ok as before, and Ubuntu is booting in 1 out of 5 attempts, but mostly freezes with a black screen. To get in contact I have to press and hold the Power-on key a while, then release the key.
Now, I decided to reinstall Ubuntu 20.04 LTS from a bootable USB-stick. Result: Windows ok, Ubuntu as before. Though, I am able to get a nice Ubuntu via '5.4.0-56 generic(recovery mode)' from grub's boot screen.
I tried different solutions to the problem from stack overflow.com and other sites, starting with setting nomodeset in /etc/default/grub and ending with boot-repair (Pastebin see below).
How do I get a normal dual boot back?
PC: Asus Zenbook UX305CA
Mmemory 7,7 GiB
CPU Intel® Core™ m3-6Y30 CPU @ 0.90GHz × 4
Graphic lvmpipe (LLVM 10.0.0, 256 bits)
Disk 256,1 GB
OS Ubuntu 20.04.1 LTS
Type 64-bit
GNOME-v 3.36.3
Window X11
Ubuntu Pastebin: https://paste.ubuntu.com/p/8ycqyWfVhF/
