[hdmkv]

@popcornmix, just making sure I should replace start.elf and fixup.dat on my Pi's SD card with your start_x.elf and fixup_x.dat? And, just rename them? Or, are you saying rename the start.elf and fixup.dat on my SD card, then copy over your start.elf and fixup.dat?

In my config, I have a hdmi_ignore_cec_init=1. Leave that alone and add hdmi_debug=0xffff?

Yes, leave whatever is in your config.txt, and add the new line.
You want to rename start_x.elf from zip file to start.elf and overwrite the start.elf on your sdcard (similarly for fixup_x.dat).

Using Epson 5025UB and build #1012, and UI switched back to 1080p/60.00 (from my temporary 1080p/50.00 fix from woronczak)...

• With hdmi_debug=0xffff, takes a while for UI to show, then after I play a video (a recent 2D 'Walking Dead' MKV 720p episode), it plays fine. But, I stop and UI blanks out. So, worse than before, when UI only blanked out after starting playback of whatever 2nd video.
  
• With hdmi_debug=0x1ffff, replacing the hdmi_debug=0xffff line, my RPi2 won't even boot up.
  

Not sure if it'll help, but let me take a video (with my standard config.txt) and UI at 1080p/60.00 and show what's happening. And, will do same with woronczak's 1080p/50.00 trick. I'll post this shortly.