stm32wb FUS footer has empty word between magic word and version

[YWor.1]

Hi.

I'm working on stm32wb for some time, handling CPU2 updates of BLE stack application.

Lately, version 1.23 was published with new FUS version, so I tried updating it with my application running on user flash. I searched for the magic word but I found something strange, empty word in the middle of the footer:

I compared it to previous version and it appear there also.

As described in AN5185, magic word is placed after FW version, so what am I missing?

Any help is welcome.

Thanks in advance.

[YWor.1 · Accepted solution]

I was missing a note in AN5185 page 26: "FUS V1.2.0 version is written in the binary as 0xFFFFFFFF to be able to upgrade from all versions of FUS", so the empty word is the version.

Thanks @Alan PORTE  for helping me.