Laptop starts only to a prompt

[Asking-Pit]

Dear Community, at first i will apologize for my bad english. I'm Peter from Germany and i hope to find here the right answers for my problem, the german communities can't help.

I've installed kubuntu 18.04 on a blanc Laptop, no dual boot sequence. The installation was without any problems, kubuntu runs good. After 14 days kubuntu starts only to a prompt like MS-DOS. Inputs like "startx" doesn't work, and "sudo startx" doesn't work, too. After starting the Laptop i can read the message "ACPI BIOS Error (bug): AE_AML_BUFFER_LIMIT, Index (0x00000000FF) is beyond end of object (length 0x20)..." and some other lines they all begin with "ACPI BIOS Error" or "ACPI Error".

If this problem is to critical i like to know where i can find the bookmarks from firefox. I can start the Laptop with the installation USB-Stick without any problems, but i can't find the entrys of the bookmark-list from firefox.

Can someone help me please? Thank you in advance.

[jlittle]

That looks like a nasty one. It's hardware related, is yours a HP laptop? Please tell us the model.

The bug reports say the fix landed in kernel 5.4.7. Ubuntu 20.04 just released is 5.4.0. One poster in the bug reports said he wasn't able to "turn ACPI off", because his hardware needs it; conceivably, that might be a work around for you, but I've no idea how you'd do that.

Perhaps someone else here has experience at installing new kernels. I have not. In theory they're available from kernel.ubuntu.com. I imagine installing a 5.4 kernel to 18.04 might be a challenge.

Anyway, the firefox bookmarks are backed up to ~/.mozilla/firefox/profile.default/bookmarkbackups/ where the profile is some random string like "km4x8qjb". The files are in some strange format, but you can copy them and import them into another firefox.