I had similar probs with mine not on itv4 Only my box wouldnt pick up sky one but would pick up sky mix. all my bers and snr where all giving me conflicting status depending on what channel i was trying to watch.... unistalled all my sushi, games, tuxwetter outdoor and any other stuff on the box like (A service File which was heavy in weight due to all my fooked up scans. instead of overwritting my file it just kept on adding same channels to my service file, thus the file was growing and taking up valuable memory. So after reducing all the dead weight from the box (ie clearing space off the memory) I found the box performed a hell of lot better. Also i noticed sky one was hop skipping and jumping around like it had its arse burnt or something. Then i clicked on... that my epg reseting problem is nowt to do with sectiond update etc. It was the box reseting epg because it was getting a better signal on some channels. Yee haaaa! I screamed as after everytime my epg went tits up i scanned OVERWRITTING THE SERVICE FILE as not to increase its weight. And low and behold the snr went up slightly everytime and the ber dropped like an asda rollback price.
At first the epg reset itself around 1nce a week. for around 3wks and now it dosnt. hope this may explain something to you pal because really im still none the wiser as to what i really did to sort out my missing channels and skipping chirping noisy squeeky channels but whatever it was the box is fine....2 1/2 months down the line. sagem dox2 running spts 1.7 uk 05... tried almost every image in the house but this ones the guy for me. ultra, gavs or super dooper and what ever the next one's are called Im sticking with this image mate. STICK WITHIT PAL around 10 month it took me seriously.
And you should have read the shite i was posting at the time.... and i know it dont help you any when you got cock nockers like me blerting on about how there box is sorted...my heart goes out to ya fella..