I recently had to replace my Slingbox Pro HD due to a power issue and when I received the new one, after using the same setup, it will no longer control my Directv receiver. I was told from Slingbox tech support that the firmware upgrade done to the Slingbox may have caused this issue. Since the presets in the setup don't list the H21, I am looking for the correct bin file. I have tried various presets and none seem to work. Has anyone else out there had this issue? Any feedback is appreciated. Thanks.
All DirectTV boxes use the same codes, so if none of them are working you have another problem. Check out this thread: https://community.sling.com/thread/3300?tstart=0
Come back if it doesn't help.