LTE bands and custom ROMS

hi everyone

Here in the UK, EE uses the following LTE bands
800 MHz (0.8 GHz)
1800 MHz (1.8 GHz)
2600 MHz (2.6 GHz)

It might have just been a bad day for signal reception, but would flashing a custom ROM (ICE in my case) affect or change the LTE bands used?

Thanks -