Öyle düşünmeyin belki sim kart ile çözülür. Son söyleyeceğim ise bu kaynakta birisi yongalara değinmiş.
1) A matter of hardware, but it is strange that a manufacturer will spend lots of money just to buy different chips than standard ones that sports by default all frequencies (supporting all frequencies by default it is a matter of economy during chip manufacturing). Maybe Qualcomm Chip just present some pins not soldered on Phone Motherboard so this works as a real "hardware" easy method to OFF definitively frequencies?
2) it is a matter of Firmware in Qualcomm Modem Chip.
Qualcomm just defines in Firmware enabled/disabled frequencies upon phone manufacturer requests, depending on market of reference (Most easy and economic solution).
3) it is a matter of 2 steps switch-on process (A) Unlocking Band in drivers (B) Activate it from firmware or somewhere else (Kernel? Or perhaps presence of 4G-LTE SIMs with correct Band activation code embedded in SIM?)
Şebeke veya sim kaynaklı olabilir.