This firmware is for video and my Asrock J3355M also fails to load video firmware, though a different version.
See my post/dmesg
http://daemonforums.org/showthread.php?t=174&page=6
One suggestion is to disable inteldrm using ukc. The details are in the following link under boot time configuration.
http://www.openbsd.org/faq/faq5.html#Custom.
There has been some activity on the mailing lists in regard to intel video firmware. My sense was that it was appropriately "placed on the back-burner" during the Spectre/Meltdown issue.