This firmware is not signed. This means you cannot restore to it in iTunes.
| Release Date | Invalid Date |
| Upload Date | 13 December 2010 |
| File Name | AppleTV2,1_4.2.1_8C154_Restore.ipsw |
| File Size | 0.26 GB |
| SHA256sum | f00c919540db121f9d4d443965366d60f97705ae1bce1e8c40505aaa3d134247 |
| MD5sum | 3fe1a01b8f5c8425a074ffd6deea7c86 |
| SHA1sum | c2b1adea595afa2b9caf633f0a820d3b66424dbf |
| Identifier | AppleTV2,1 |
cd ~/Downloads.idevicerestore -e AppleTV2,1_4.2.1_8C154_Restore.ipsw and press Enter.