I have a Sprint Mega SPH-L600 that I got with a 4.4 ROM that I just cannot seem to return to stock. I have tried all of Silesh's GT9205 ROM's with no avail. I have tried everything I can think of. I've downloaded every version of the stock 4.2 I can find but it always boot loops. I have also tried all of the GSM ported ROM's but they are the only thing that will flash to my phone. I have the custom Philz recovery that's how I'm flashing the ROMs. In download mode I don't see anything about knox. I don't believe I have it. My modem is still running the NA7. Is there any way to downgrade? My main goal is to open the diagnostic ports. But the CDMA dialer codes are non-existent in this GSM ROM. I am trying to flash this phone to Page Plus. What a hassle! Is there any hope Obi Wan Kenobi?!?! Thank you.