Hope you have updated the firmware in the below order.
BIOS(reset) ->BMC(reset) -> FRUSDR(Ac cycle).
While updating FRUSDR please select the chenbro chassis (see the serial #) and make sure you reset the machine after updating the f/w.
If still issue is seen, please
Clear the SEL using SELVIEW tool and Do the AC cycle.
and get the SEL message. it should say exact problem.
Note: Since you said, Chenbro chassis is vaildated and running fine with other machine, i didnt do research on supported chassis.
makesure you have right CPU Heat sink ( Active/passive) - check for the supported heatsink wrt chenbro chassis.
Like to receive the SELVIew message.