WP77 firmware release 5.1 swi-linux-src won't build

Steps to repeat:
Use leaf to get the swi-linux-src: leaf getsrc swi-linux
Run make image_bin in the source directory.

Nothing PROVIDES ‘mdm9x06-image-minimal’

I noted that in all previous builds the WP77 is an mdm9x28.

If you build the source after running ‘leaf shell’, it fails.
This means your default shell for sh needs to be bash for the build to succeed.
leaf shell configures the device as an mdm9x06 when it should be an mdm9x28.