On 2018-10-10, Zbyszek Żółkiewski <[email protected]> wrote: > Is there guide somewhere on how to load custom microcode for CPU on OpenBSD?
There isn't. If it's an intel cpu, you could overwrite the file in /etc/firmware/intel for your cpu family/model/stepping (taking care with fw_update). On -current this is shown in the cpu attach line in dmesg, e.g. with cpu0: Intel(R) Xeon(R) CPU E3-1225 v3 @ 3.20GHz, 3392.62 MHz, 06-3c-03 the bootloader will look for ucode in /etc/firmware/intel/06-3c-03. Note: there's no ucode loader for non-Intel CPUs yet. And if you have a bad microcode file you might have some hassle disabling it (booting from install media and mounting the partition on the disk to move it out the way is probably the simplest).
