Unplugging the connector that feeds the 3 buttons still wouldn't boot the first time. I left it for 15 minutes, 3 times and just stayed on the boot screen.oh right, they are.
if you want, you could just completely substitute them for software buttons, but i dont know if you want to do that or not.
hmm, well i would recommend first trying to flash the other firmwares
ive already tried flashing a multitude of different firmwares to my sgh-m919v and it never bricked the phone. i hear that flashing the modem files may brick it, but ive never actually bricked mine, so you may want to try messing around with different firmware versions. flashing i337m and m919 firmware kept the phone perfectly functional (it still wouldnt boot into this rom. im now 200% sure its the display, the one part i really didnt want to replace..)
also, it seems like the home button bypasses most of the circutry (just guessing based on my experiences) because all my softkeys are physically broken (the little softkey control board is crunched) but the home button still works. im pretty sure it goes on a different rail, so if you're experienced in microsoldering, you could figure something out (not that it'd be a very good solution judging by the fact that you might aswell just use software buttons).
anyways, id first recommend just trying to boot it without the buttons connected at all, just to see if it boots like that. if it does, you can then try using the software solutions like flashing different firmwares or using software buttons if you're confterable with them. if it doesnt work AT ALL then you're probably looking at getting some new softbuttons/board or trying to debug further.
Wonder if jdcteam could edit the code based on the error log...