Server using SuperMicro X11SCL-IF stuck at boot in MRC execution


at boot time my home server hangs in the “PEI Intel MRC Execution”.
Board: SuperMicro X11SCL-IF

Question 1: USB mouse and USB keyboard do not seem to be powered at this time.
(LED of the mouse is off, LEDs of the keyboard are off).

  • Is this normal or when will the USB interfaces be powered?

I have two 8GB memory bars KSM26ES8/8HD, 8GB 1Rx8 1G x 72-bit PC4-266, CL19 288-pin DIMM installed.
The build suggestion suggests KSM26ES8/8ME.
“HD” and “ME” seem to differ only in “Hynix D-Die” and “Micron E-Die”.

  • Could this difference be the cause why the server seems to hang in MRC Execution?
  • How long does the MRC Execution normally take (on the first boot)?

I also tried to populate the server with only one bar in DIMM-B each. Unfortunately this did not change the result.