[SeaBIOS] ps2port: `keyboard self test failed (got ab not 0xaa)`

[Paul Menzel]

Dear SeaBIOS folks,

On the laptop TUXEDO Book BU1406 (Clevo N240BU) with coreboot [1] and 
SeaBIOS master, the internal PS/2 keyboard often does not work.

SeaBIOS (version rel-1.13.0-45-g6ada228)
     […]
     /7aa38000\ Start thread
     |7aa38000| Discarding ps2 data 41 (status=13)
     Searching bootorder for: HALT
     /7aa35000\ Start thread
     Found 0 lpt ports
     Found 0 serial ports
     |7aa38000| keyboard self test failed (got ab not 0xaa)
     \7aa38000/ End thread
     […]

Kind regards,

Paul

[1]: https://review.coreboot.org/c/coreboot/+/43760/
      "mb/clevo/kbl-u: Add Clevo N240BU as variant"