keygen.zip in iso or img root directory,for chr image it's in /flash/rw/disk/ directory,same as winbox file manager directory
run unzip keygen.zip
run keygen.exe software_id

install option-{version}.npk package
run telnet to routeros with username devel and password is same as admin

install python3-{version}.npk package
run telnet to routeros with username devel and password is same as admin
run python -V

Sign，Verify，Create, Extract npk file.

Patch public key and sign NPK files

Modify netinstallexe to enable network installation of NPK files that have been resigned in ISO

By adding static domain name resolution in RouterOS, the NPK file that has been resigned in ISO can be installed during the upgrade process.