Your VTX does not support low band by default. make sure your region allows low band before unlocking it.
Please use the firmware below to unlock the low band.
Unlock_Lowband.zip
Update the firmware in the zip to your vtx.
Vtx powered on. You will see the blue led flash 5 times and then turn off, indicating that the low band is unlocked successfully.
Power off the VTX.
Update the vtx to support low band firmware, your vtx will start to support low band.
how to switch to low band channel
vtx menu
msp vtx
keypad
540P60
You can set to 540p60 at camera menu.
Only nano90 camera supports 540p60.
Low band
Frequency
Range 5312MHz ~ 5635MHz
Unlock low band
Your VTX does not support low band by default. make sure your region allows low band before unlocking it. Please use the firmware below to unlock the low band. Unlock_Lowband.zip
how to switch to low band channel
540P60
You can set to 540p60 at camera menu. Only nano90 camera supports 540p60.
Goggle PR
https://github.com/hd-zero/hdzero-goggle/pull/321