I've just bought a samsung galaxy s4 (i9505) (a used one not new) and i flashed Imperium v7 and modem GNF1 and bootloader GNF1 (initially the phone was on stock 4.2.2 and the problem was already there).
My problem is that i don't get the network i rarely see two or three bars but it directly goes to zero (i can see the no network sign) and stays like that until a reboot (as said it drops to no network very fast).
So my question, is it software ? (should i flash the latest samsung stock firmware ?) or is it hardware ? (replace the internal network ship ?)
Or is it a common problem on S4 i9505 and no solution cannot be found ?
Could it be related to CSC ?
Anyway, i hope anybody can help me because i really like this phone and the rom that i just installed ..
Feel free to ask me about additional informations.
EDIT : I already tried :
1) the modem+bl FNDA => same result
2) force the phone to gsm only => same result (maybe better but even it solves the problem there is no point to not having 3g activated all the time)