Samsung claims that the speaker internal software (firmware) is opensource. As far as I can see, it's based on an opensource technology stack but the latest firmware files are not available as source files. The speakers are based on an ARM Linux opensource stack and some code is available on the url below:

Speaker are running jQuery and Bootstrap, see:
http://speaker ip address:8001/resources/js/jquery.min.js
http://speaker ip address:8001/resources/js/bootstrap.min.js

Image1 gives an impression of the WAM750 package.

Analysing the firmware file

"binwalk" is one of the primary tools used for analyzing, reverse engineering and extracting data from the firmware image. You should be looking for binwalk to identify the type of file system in use, ex. squashfs filesystem.

Another tool is "firmware mod kit"
more info: https://www.owasp.org/index.php/IoT_Firmware_Analysis#Analyze_Firmware_File

Decrypting the Firmware file

Looks lke there are possibilities, see below:

NOTE:

A development team from Samygo.tv has created a tool for decrypting/encrypting most of the
Samsung TV firmwares4 . Additionally, for every file in this firmware update package (USB
update) there is also another file that contains a cmac signature (fugure 2). This signature
guaranties the integrity and authenticity of the firmware. Hence, the TV’s USB update procedure
requires a firmware that is cryptographically signed by Samsung

See: https://forum.samygo.tv/viewtopic.php?f=16&t=11348

https://forum.samygo.tv/viewtopic.php?t=6262