I know that it is just a few days after the new Navigator board arrived and I had a play with it last week.
I compiled and used Sub4.1 firmware (which I pulled from Github) with custom frame for ROV. Before I compiled, I used the configurations for Pixhawk1 boards.
However, when I tried to upload the firmware, there was an error popped up as shown, does that means the file is corrupted and cannot be used or is it using wrong board configuration option ? Thank you for your response !!
While their input and output functionalities are similar, the Navigator and Pixhawk1 are different devices, and have different hardware that needs to be configured.
I asked internally what the process is for building ArduSub for Navigator and was told it should be the same but using ./waf configure --board navigator instead of ./waf configure --board pixhawk. You can use ArduSub-beta to checkout 4.1, although you seem to have figured that out (or something equivalent) already
On the file type, instead of the .apj files that we generally use for the Pixhawk,
Which version of Ubuntu and GCC did you used, we found out that Ardusub can only be compiled with GCC 8.x and 9.x (our were 9.4.0) and using Ubuntu 20.04 (22.04 does not support with enough packages). It can still be compiled with newer version of GCC but will have no comms with Qgroundcontrol