serial console install at 115200 bps

[76nemo76%gmx.ch@localhost]

Hi All,
      Almost all is alreay in subject. I plan to install NetBSD 7.02
on a PCEngines APU2 computer (https://www.pcengines.ch/). Basically,
this machine is an AMD64 PC without graphic card but with
a serial console working only at 115200bps.

The installation image (boot-com.iso) works at 9600bps. I would know
if it is possible to change the speed of the serial console
during boot (on openBSD it is possible to pass
a command "stty com0 115200" and in FreeBSD to add a parameter
in ISO image to boot with a serial console at 115200).

It is impossible to change the speed of serial console in BIOS
of PCEngines APU.

Without a solution, I think the only possibility is to start
at 115200, then disconnect from serial console and reconnect at 9600.

This is not very confortable but perhaps doable.

Thanks for ideas and help.

Best regards

Alan