If it says "old image invalid", it means it has an old SSL, so you need first to flash the latest original SSL (87 or 88), then reboot the box into flash mode and flash the OpenPLi image as it uses the latest SSL bootloader.

TS
_________________________
DM8000, DM800se, DM500HD, DM800HD, DM7025, DM7020s, DM7000, DM500s
VU+ Solo, VU+ Uno, VU+ Duo, Kathrein UFS910
Tivusat, TNTSat, Fransat, SSR/TSR, BBC1-2-3/ITV
DE-OpenBlackHole 1.4 image : http://www.openblackhole.com/