6.4 works out-of-the-box on my Lenovo T400 with Libreboot version 20160902. OpenBSD on this laptop has been my daily driver since late 2018.
The only caveat is that Libreboot cannot chainload OpenBSD's boot loader, so I cannot boot the
recommended way. Instead, Libreboot's built-in grub2 needs to load the bsd kernel directly. This is the relevant entry from my grub.cfg:
Code:
menuentry 'OpenBSD 6.4' {
kopenbsd -r sd0a (ahci1,openbsd1)/bsd
}
Booting the kernel directly this way doesn't break anything AFAICT.