Hi Rafael, Sorry about the timing of reporting this regression. I just noticed that overriding the DSDT (*) from the initrd will not work in 5.12, this is caused by: commit 1a1c130ab757 ("ACPI: tables: x86: Reserve memory occupied by ACPI tables") This makes the initial acpi_locate_initial_tables() call happen earlier then before, but the acpi_table_upgrade) call in arch/x86/kernel/setup.c is not moved up, so the tables in the initrd are now only parsed and saved after the initial ACPI table scanning has already been done. I guess fixing this might be as easy as moving the acpi_table_upgrade) call higher in arch/x86/kernel/setup.c but I'm not sure if that is save to do. I've several devices with ACPI tables which are so broken that they need an override. I've reverted the commit from my personal tree for now which avoids the regression. Regards, Hans