<SOLVED> Hibernation from LM 21.2

[dan63043]

Setting up hibernation seems to change from version to version. Couldn't find anything relevant to Linux Mint 21.2. What I'd like to do is hibernate from "Battery Applet with Monitoring and Shutdown (BAMS) (batterymonitor@pdcurtis) Version 2.0.0

What I've done so far:
$ cat /etc/initramfs-tools/conf.d/resume
RESUME=UUID=895458ff-b786-461e-9aef-f41d6ffabbe7

sudo update-initramfs -u -k all

$ grep hibernate ~/.local/share/cinnamon/applets/batterymonitor@pdcurtis/5.4/suspendScript
systemctl hibernate

$ reboot

Then I let the battery run down, and expected it to hibernate at about 10%. Instead, when I restarted the machine, the battery was completely drained. This is on a fairly old AMD laptop that has 20GB of RAM and 32 GB swap. The RESUME UUID matches the swap partition (which is always completely free.)

Any ideas?

[dan63043]

I deleted the "resume" file and reran update-initramfs -u -k all

In /etc/default/grub, I put:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash resume=UUID=895458ff-b786-461e-9aef-f41d6ffabbe7"

Then I rebooted and tested hibernation, and it worked.

[christiand]

I'm on LMDE 6 "Faye", swap partition encrypted inside LVM. To get resume to work I had to append resume=UUID=swap-partition-uuid inside /etc/default/grub.d/50_lmde.cfg in row GRUB_CMDLINE_LINUX_DEFAULT=...