- Disable opkg signature checking for unsigned SecuBox feeds
- Add retry logic (3 attempts) for repository validation
- Add retry logic (3 attempts) for opkg update
- Add retry logic (3 attempts) for package installation
- Increase wget timeout from 10s to 15s
- Update slipstream firstboot to also disable signature checking
- Fix CORE_PACKAGES to use packages that actually exist
This fixes the "Unknown package" errors when installing from
repo.secubox.in caused by opkg discarding unsigned package lists.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>