I have a Toshiba Satellite laptop with i5-5200U and integrated graphics running xubuntu 16.04.4 LTS (along with windows10 in a dual-boot setup). It has been working like a charm for more than a year, until a few weeks ago when the kernel was upgraded to 4.4.0-119-generic, and subsequently to 4.4.0-121.
Now it fails to boot. Grub starts fine, but when I select Ubuntu, it only says "Loading Linux 4.4.0-119-generic" and then "Loading initial ramdisk ..." and after that it just hangs forever with these two lines in a black screen. I've tried booting it in recovery mode but the problem persists. And the same happens with the newer 4.4.0-121 version.
However, with kernel version 4.4.0-116 it works perfectly. Any ideas what has changed since kernel 4.4.0-116 to cause this black screen problem? There are similar(ish) problems described here, but none of the solutions worked for me.
(Windows boots just fine, but I rarely use it.)
Edit: some links to similar questions were requested, but I didn't originally post them because none of them actually described a similar problem.
This one came pretty close, but didn't help:
Here are a few more with similar symptoms.
Kernel 4.4.0-109-generic fails to boot but 4.4.0-104-generic works fine Lenovo fails to boot 4.4.0-109 Cannot boot ubuntu 16.04.3 with kernel version greater than 4.4.0-89 Ubuntu 16.04.1 LTS with kernel 4.4.0-34 does not boot after upgrading