Hello,
The new kernels 5.12.4.x expose an ACPI bug that has been mentioned by many users (not necessarily using siduction). I have a processor Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz, an American Megatrends BIOS, version: 5.12. dmesg yields many lines of the form
May 16 19:41:40 siduction kernel: ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PR00._CPC], AE_NOT_FOUND (20210105/psargs-330)
In my case, the system boots and still seems somehow usable, but I guess that a patch is needed to avoid the above warnings. I have reverted to kernel 5.11.18 to be safe.
Many thanks for the hard work on siduction!