I'm running amd64-current on an ASrock J3355M and recall a similar issue installing from a USB thumb drive. My suspicion was that the BIOS treated the drive as an unknown input device like a keyboard or mouse.
I was able to install from a DVD/CD drive. If you do not have one, you may be able to a PXE install or Disable the legacy usb keyboard/mouse settings in the BIOS. The other issue I had was frequent lockups due to buggy C-state power savings. It works fine with Bios setting C-state=1 On 2018-11-14, Andrew Lemin wrote:
Hi, I am running an ASRock J4105B-ITX board and wanting to run OpenBSD on this. https://www.asrock.com/MB/Intel/J4105B-ITX/index.asp#BIOS It boots up, and at the 'boot>' prompt I can use the keyboard find. However after it boots up, the keyboard stops working, and no disks are found by the installer (used auto_install to send test commands). It appears that there is no chipset support, for the Intel Celeron J4105 CPU from what I can work out. To test that it was working fine and is just OpebBSD which is not working, I installed Linux and have included the dmesg below (from Linux). I cannot run a dmesg from the OpenBSD installer as I cannot use the keyboard etc. Will support come for this SoC architecture? Or am I better of selling this board? Think its a Gemini Lake SoC Chipset;
-- J. Scott Heppler
