[BlueOnyx:25560] BO5209R GUI broken because of wrong PHP version?

[Blueonyx@Ceelie.info]

Hi Michael and the BO crew,

On the old 5209R server I can reach the GUI page by http://serverip:444. Nothing happens though after root or admin credentials. Today I read another post saying installing other php versions will mostly brick the GUI.
I tried to install Twonky on the server, and the manual told me to install some php shizzle. So I guess that's why the gui is broken.
How do I get rid of the faulty php's and re-install the glorious BO GUI php version, plz?
Cheers,

Arie