This is a brand new install so I don’t have an older kernel to boot into as the OP above has.
How do I update my install to the 6.15-rc2 kernel if my current install is broken?
I have Ubuntu Server 22.04 on the same laptop (2015 MacBookPro) that boots just fine and can mount and write to the partition that contains /boot of my 25.04 install.
I can also boot back into the Live CD for 25.04 as well (perplexes me why the Live CD boots just fine)
Is this a the kind of task I would use chroot (along w the bind mounts) while booted into Ubuntu Server (or back into the Live CD) and install the rc2 deb files (sudo dpkg -i *2025041413*) or is there a different way of going about it?
My understanding from the discussion on Ask Ubuntu is this has been fixed upstream so just looking for a way to get up and running with 25.04.
@rubi1200 not certain why you moved this thread as this issue appears more related to 25.04’s pre-release status (ie. a defect in the kernel) than a general installation problem.
booted into my local Ubuntu Server 22.04 install (alternatively, you could boot into the Ubuntu 25.04 live environment)
mount the Ubuntu 25.04 partition (eg. sudo mount /dev/sda3 /mnt)
for i in /dev /dev/pts /proc /sys; do sudo mount -B $i /mnt$i; done
chroot /mnt
cd <dir with rc2 .deb files>
sudo dpkg -i *2025041413*
reboot
default selection in GRUB2 should be fine and it will load the initial ramdisk (instead of getting stuck) and present the log on screen. Log in and you’ll get to the desktop.
Please note that the mainline kernel builds are highly insecure, do not update and are not meant to be used for more than verifying bugs when a kernel team developer asks you in a bug conversation to temporarily install them…
They are lacking essential (security) patches and use the wrong config.
whoa - I had no idea - thank you for letting me know!
given updating to the mainline was the solution that worked (and also verified by others) - is there an alternate channel/method we should be using that does not compromise security?
Sadly I fear for something official you will have to wait until the next proper HWE kernel hits the archive…
The missing patches will likely also have some functional impact as well, some userspace apps expect certain kernel features to be available (i.e. snap packages (particulalry firefox), lxd containers and other bits will not find all the expected features) so you might hit issues down the road.
It is still very curious that the 6.14 kernel from the live image seems to boot and run just fine though, which kind of points in other directions than the kernel for your issue (yet adding 6.15 to the install seems to fix it for you)