I followed exactly the steps you said :

Install the image below "openvision-enigma2-develop-7.2-r18-dm800se_Japhar_v6" in the receiver, then do not Reboot receiver, but go back to the page and install "secondstage-dm800se-84-allsim", then restart the receiver , the required minimum settings are made, we enter the Menu >>> Plugins here we look for if we have JAM installed (Japhar Addons Manager, this: japhar-addons-manager_5.2_DM_oe20_mips32el) if it doesn't exist we copy it on a stick, we insert the stick in the receiver and- I install it with the help of the remote control.
After installation we restart the receiver, then enter the JAM menu, select the second menu option (Support Japhar Sim v3-v5-v6), go to the end of X_FrontSlot Sim Flash DM800HDseV1 v6 ​​>>> OK and rewrite sim ....., then turn off the device / receiver and change the sims.

P.S.
After I made all these settings I wanted to put another image, after installing another image it shows me No Ca Found .