Hello.
Recently, I purchased the Radxa CM5 V2.21 and I’m planning to test it on the Raspberry Pi CM4 IO board.
I’m following the instructions on the following page to install the OS on eMMC:
https://docs.radxa.com/en/compute-module/cm5/radxa-os/low-level-dev/rkdeveloptool
I’m having trouble locating the Radxa CM5 V2.21 loader file in the 'sudo rkdeveloptool db ’ section and I need some assistance.
Where can I find the loader file for Radxa CM5 V2.21?
Probably on their github… give a look Im still waiting on mine… lets see how it goes.
I could not find it either, however the Rock 5B SPI loader file works.
https://dl.radxa.com/rock5/sw/images/loader/rock-5b/rk3588_spl_loader_v1.08.111.bin
I opened a Github issue for this to update the docs to its source.
I found github and build loader.
And flash radxa-cm5-rpi-cm4-io-6_1_bookworm but mouse/keyboard didn`t work on Rraspberry pi cm4 IO Board.
It seems like power isn’t being supplied to the USB port. 
Issue closed 
having same issue，how to fix it
Radxa updated the loader
https://dl.radxa.com/rock5/sw/images/loader/rock-5b/release/rk3588_spl_loader_v1.15.113.bin
usb didnt work on cm4 board too，how to fix it[quote=“nemo1, post:4, topic:20888”]
mouse/keyboard didn`t work on Rraspberry pi cm4 IO Board
[/quote]
Ah, See this issue. I solved it like this.
https://github.com/radxa-build/radxa-cm5-rpi-cm4-io-6_1/issues/1
rebuild linux kernel？