AM623: When use signed ti-dm firmware

Part Number: AM623

Tool/software:

There are two ti-dm file, one is signed, only the unsigned one is used in binman.dtsi, when use the signed one?

tony@ubuntu22:~/ti-processor-sdk-linux-am62xx-evm-11.01.05.03/board-support/prebuilt-images/am62xx-evm/ti-dm/am62xx$ ls -l
total 384
-rw-r--r-- 1 tony tony 194484 Jul  6 09:27 ipc_echo_testb_mcu1_0_release_strip.xer5f
-rw-r--r-- 1 tony tony 196164 Jul  6 09:27 ipc_echo_testb_mcu1_0_release_strip.xer5f.signed