The secondstage-dm800se-84-allsim.zip perfectly works, you naturally have to unzip it, to then use the .nfi file in it.

As explained in the procedure, you need to have the old sim in the box, press the frontpanel button to set to Flash mode, then flash the box with the ALLSIM SSL. This done, then you turn off the box, replace the Sim and put the Japhar Sim. Then boot the box pressing the frontpanel button to set it to flash mode to flash a Japhar Image from the DM800HDseV2 section. Just for your information... we never told to press the back button to flash something into the box... as that button just loads the Sim2 SSL... so it would never work.

TS
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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/