I have found out LB2 cannot detect black and white camera's (thermal) video signal via AV input,
it can only be used with color cameras
hope DJI will fix it in coming new firmware.

The straight AV/HD outputs on the Lightbridge 2 is strictly for standard FPV cameras. If you are looking for thermal imaging, the only supported thermal imaging camera for the LB2 is the Zenmuse XT.

DJI-Jamie Posted at 2016-7-13 00:04
The straight AV/HD outputs on the Lightbridge 2 is strictly for standard FPV cameras. If you are loo ...

if i want to use black and white FPV camera, means LB2 doesnt support ??
moreover LB1 can support it.
i guess new versions should supports more functions and advantages than old one