I recently picked up an i717 and am in the process of sorting it out. It was originally a Bell phone, though of course it's unlocked these days. I've been hacking at various Android phones for years now and have managed to work through just about everything, but this has me stumped...
I've tried almost all the 4.4 roms, and most of the 4.3 as well. I've tried various kernels/modems/combinations/etc. I've used CWM and TWRP. They all invariably lead to the phone either rebooting constantly from the "optimizing apps" dialogue, or a few times I've made it to the welcome screen, but it's always just up for a minute or two, crashes, then reboots. I haven't found a live download for 4.2 yet, so I don't know if it would work or not. 4.1 stock and Padawan run just great. I've been doing multiple full wipes before installation, flashing the rom a few times, then hitting the caches a few more times for good measure. I can't imagine my flashing technique being at issue here.
I do know that there is at least some physical damage to the phone. The capacitive buttons don't work. But it doesn't see immediately obvious to me that these would be related. Of course, I've seen stranger things. Running Padawan the phone will hum right along at max speed all day with no apparent issues, so that side of the hardware seems okay.
Sometimes CM roms will end up at the CM welcome screen and pop up a "com.android.acore has stopped" dialogue. But the constant reboots are there on every rom I've tried.
Does anybody have any ideas?