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Since I've installed kubuntu 19.04 my computer is not able to boot all the time. I thinked it was a grub option because some things are changed from the previous version 18.04 (which works fine for me), but in fact I can make nomodeset [nouveau/nvidia].modeset=0 or many other strange things, my computer just get stuck on black screen once in five. By the way, it makes the same trouble with the installation media

And if I press the esc key on boot, it just stay black and doesn't change anything ...

config of my pc : i7 8650U + gtx 1050m

(Please correct me if my english is bad and you want to help me ;-) )

Cyanodom Telladéon
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  • To help debug the problem, next time you see the purple screen just hit the "Esc" key so you can see the boot messages. If it's stuck, you'll be able to see why. You can edit your question with that info so we can further help you – Felipe May 14 '19 at 20:45
  • Thank you, now I 've installed kubuntu but when I press esc nothing changes and ctrl-alt-f1/f2 etc dont makes anything, I can also try to boot manually by the grub commands and in fact the boot command seems to be executed once on five which makes grub do the same, if it does not, nothing happening on screen. – Cyanodom Telladéon May 15 '19 at 22:00

1 Answers1

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In GRUB, press e to edit the linux startup command line and add dis_ucode_ldr at the end of the line that starts with linux /boot/... so that the line will look something like:

linux    /boot/vmlinuz-4.18.0-20-generic root=UUID=63771674-8044-4df4-\
         b700-17bcc857432d ro quiet splash $vt_handoff dis_ucode_ldr

and you'll be able to boot.

(Remove quiet splash if you want to check the system boot logs).

Add the same parameter dis_ucode_ldr to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash dis_ucode_ldr"

then run

update-grub

and then you should always be able to boot, as-is, so without editing the command in GRUB.

See - and if possible, subscribe to - this Ubuntu bug tracker for more information:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1829620

Bludzee
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  • it seems to work perfectly but I dont know how to make this question in solved state ... sorry – Cyanodom Telladéon Jun 18 '19 at 00:17
  • A big thanks to you you solved my life XD, can you just explain what is this option ? and what was the problem ? – Cyanodom Telladéon Jun 18 '19 at 00:19
  • dis_ucode_ldr disables the automatic loading of Intel embedded software updates from the Linux kernel at boot. You need it because of an issue that prevents some ASUS ZenBook laptops to boot with a recent Intel microcode (ASUS and Intel are working on it). When the issue is solved (see the Launchpad tracker), we'll have to remove the dis_ucode_ldr in order to benefit from the ucode package update (security, etc.) The microcode update can also be loaded by the BIOS, so check for BIOS updates as well (update via BIOS is the best option). – Bludzee Jun 18 '19 at 08:10
  • See also the following tracker (not limited to Ubuntu or UX533):

    https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/1

    Apparently, new BIOS versions are available that are supposed to fix the issue!

     – Bludzee Jun 18 '19 at 13:40