[coreboot] Information about "HP-Compaq 8200 Elite SFF"

Hi guys Thanks a lot for the great work on coreboot. I'm looking for install coreboot on my "HP-Compaq 8200 Elite SFF", so I was happy to found your site: https://doc.coreboot.org/mainboard/hp/compaq_8200_sff.html In this documentation stands: "Internal programming: The SPI flash can be accessed using flashrom.". So I tried to read the factory-BIOS with flashrom but without success. Please consult the annexed log-file. Could you please explain-me why reading with the internal-programmer doesn't work for me? Thanks in advance Best regards Dario