Invalid K30 5G V12.0.2.0.QGICNXM stable can't enable 5G

[bintsai]

Original with V12.02.02 CN stable version ROM, it can see the 5G enable/disable option button, but flashed to EU stable version, can't enable 5G.
Also miss the 5G option button.

 

[Igor Eisberg]

On international ROMs there is no 5G switch, it has a 5G choice in "Preferred network type".

 

[bintsai]

But can not saw 5G choice in Perferred network type

 

[bintsai]

Add screenshot

 

[Igor Eisberg]

Add screenshot

You're not even supposed to access this screen. This is not intended for end users.
Settings -> SIM cards & mobile networks -> SIM 1 -> Preferred network type