I managed to successfully root and flash a HTC one, a HTC desire, my good Samsung s4, and then..
A friend of mine has an LG Optimus g pro f240s, bought from Amazon - from Korea SK Telecom, we live in Europe (Austria).
As we had some security problems with the old (not updated for a long time) software 4.2.2 early this year, we decided to flash a custom Rom.
That is where the trouble begins. Now, i managed to root the LG Optimus G PRO and to install a Cyanogenmod ROM.
Everything was fine, except there has been NO SIGNAL.
Then, a week later - the new Stock software came in 4.4.2 and i have tried to update it through the official software, and i also have followed the guides here on XDA developers (the ones with adb interface, marwin2, https server, and so on). Nothing.
Then i have discovered that my WIN 8 computer is not the ideal environment for this operation, so i've installed WIN7 and tried once more.
I have been able to flash the stock based LGViet Rom 4.4.2, also found on this forums. Still have been getting service disabled.
Then the official APP from LG has finally been reading the phone, so i have made an official update, now having the official - stock version of 4.4.2 LG SK Telecom software.
The modem reads the same one that was there upon buying the phone (original one), the phone behaves normally, but - SERVICE DISABLED!!!
Please help, i have no root, no custom recovery now, but a very good looking tablet without being able to do phone calls!
I have been thinking - could this be an SIMLOCK issue? I have bought the unlock codes, but i do not have the original SK Telecom Sim, so there is no way to enter them. I have tried these codes 2945#*240# or 2945#*975#, but there is just NO POP UP menu to enter the codes!
What should i do to get the service working?
the phone reads phone number and IMEI correctly,
Model nr LG-F240S
Serial number correct
Android version 4.4.2
Build Nr KOT 491.F240Se
SW Version F240S20e