The netX flasher sources can be built with the MBS docker image from Muhkuh.
To start the MBS container and attach to it:
docker compose up -d
docker compose exec mbs bash
When starting the container for the first time:
# Install required tools
apt update && apt install -y python3-pip && python3 -m pip install gitpython
# Disable git safe directory
git config --system --add safe.directory '*'
To build the netX flasher sources:
# Build all targets
python3 mbs/mbs
# Build for a specific target
python3 mbs/mbs --netx=NETX90