notes:
1) Datecode 1A: Use get_applicable_version.pkg to receive lower/upper UDP broadcasts or use fake lowverchk PUP to get it onscreen. If minverchk is 3.50, it is downgradable to 3.55. If minverchk is 3.56, it has metldr and fails downgrade to 3.55 with blackscreen and shutdowns in 1-2sec without blinking LEDs/beeps but it is hackable because you can install 4.xx MFWs by using 4.30 checkoff, which allows you to install without downgrading (requires Hardware Flashers)
2) Datecode 1B : Not downgradable to 3.55 but might be hackable. Use get_applicable_version.pkg to receive lower/upper UDP broadcasts or use fake lowverchk PUP to get it onscreen. If minverchk is 3.56, it has metldr and fails downgrade to 3.55 with blackscreen and shutdowns in 1-2sec without blinking LEDs/beeps but it is hackable because you can install 4.xx MFWs by using 4.30 checkoff, which allows you to install without downgrading (requires Hardware Flashers). If minverchk is 3.60, it has new metldr2 of 63.776 bytes and fails downgrade to 3.55 with blackscreen and shutdowns in 8sec without blinking LEDs/beeps and is not hackable