I upgrade to v1.9.0-rc0, but the Sik Telemetry Radio do not work?

the version is px4_fmu-v2_default.

I burn v1.8.2, the Telemetry Radio work well
Any one else have this problem?

Does your FC capable of 2MB flash memory? If does, upgrade the bootloader so it can upload the px4_fmu-v3_default.px4. then try again.

Good luck.

I connected the Telemetry Radio into the TEL2 port. switch to TEL1 port, and it works.

For Telem 2, check the docs here: https://docs.px4.io/master/en/peripherals/serial_configuration.html