Current Native Call Recording CSC for Samsung are as follows;
Bangladesh (BNG) Call only
Thailand (CAM/MYM/THL) Call + SPay
Egypt (EGY) Call only
Israel (ILO) Call only
Laos (LAO) Call only
Libya (BTC/LYS) Call only
Nepal (NPL) Call only
Sri Lanka (SLK) Call only
Allergy (TMC/WTL) Call only...
Unfortunately you can't flash a boot loader from a different version, so the U1 has to stay a U1, B has to stay a B. Since the U1 is just sold in the US, unless one of the carriers unlocks eSIM or Call Recording, changing the CSC is useless.
Only way to change CSC currently is via ODIN, and you have to flash a non-Common CSC, ie. if you keep flashing the OMC_OXM your CSC will stay the same.
Download Odin 3.14.1
Download SM-F926B_XID_F926BXXU1AUG8 from your favourite firmware download site
Flash AP/BL/CP/CSC using ODIN, make sure for CSC you load the CSC_OMC_OLE and NOT the HOME_CSC
XID version enables call recording and e-SIM on your SM-F926B/DS
I've got a C6506 and when I flash the kernal and then the rom, I don't get any GSM signal at all. Its like the GSM module doesn't activate, baseband version says unknown, any ideas?