asked my cpu supplier and got this answer:Ok, works done, bios upgraded to F8. Same scenario - after change CPU to 8222CL immediately red led (SIO_LED1) shows up. Even the q-code 7-segment display remain dark. I attached two photos below.
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"There are some batches of C621 WD12 that are older and do not support oem processors. C621 WD12 IPMI should all support"