AppleTV Firmware Download version.

1.0.0: OS-dot-DMG 1.0.dmg
1.1.0: 2Z694-5248-45.dmg
2.0.0: 2Z694-5274-109.dmg
2.0.1: 2Z694-5387-25.dmg
2.0.2: 2Z694-5428-3.dmg
2.1.0: 2Z694-5485-1.dmg
2.2.0: 2Z694-5499.dmg
2:3:0: 2Z694-5573-24.dmg
2.3.1: 2Z694-5587-18.dmg
2.4.0: 2Z694-5660-029.dmg
3.0.0: 2Z694-5789-067.dmg
3.0.1: 2Z694-6004-003.dmg
3.0.2: 2Z694-6013-013.dmg
4.1.0: AppleTV2,1_4.1_8M89_Restore.ipsw
4.2.0: AppleTV2,1_4.2_8C150_Restore.ipsw
4.2.1: AppleTV2,1_4.2.1_8C154_Restore.ipsw
4.3.0: AppleTV2,1_4.3_8F191m_Restore.ipsw
4.3.0 (Build 8F202): AppleTV2,1_4.3_8F202_Restore.ipsw
4.3.0 (Build 8F305): AppleTV2,1_4.3_8F305_Restore.ipsw
4.3.0 (Build 8F455): AppleTV2,1_4.3_8F455_Restore.ipsw
4.4.0: AppleTV2,1_4.4_9A334v_Restore.ipsw
4.4.1: AppleTV2,1_4.4.1_9A335a_Restore.ipsw
4.4.2: AppleTV2,1_4.4.2_9A336a_Restore.ipsw
4.4.3: AppleTV2,1_4.4.3_9A405l_Restore.ipsw
4.4.4: AppleTV2,1_4.4.4_9A406a_Restore.ipsw
5.0.0 (ATV 2): AppleTV2,1_5.0_9B179b_Restore.ipsw 
5.0.0 (ATV 3): AppleTV3,1_5.0_9B179b_Restore.ipsw
5.0.0 (ATV 2): AppleTV2,1_5.0_9B206f_Restore.ipsw
5.0.0 (ATV 3): AppleTV3,1_5.0_9B206f_Restore.ipsw
5.0.2 (ATV 2): AppleTV2,1_5.0.2_9B830_Restore.ipsw
5.0.2 (ATV 3): AppleTV3,1_5.0.2_9B830_Restore.ipsw
5.1.0 (ATV 2): AppleTV2,1_5.1_10A406e_Restore.ipsw
5.1.0 (ATV 3): AppleTV3,1_5.1_10A406e_Restore.ipsw
5.1.1 (ATV 2): AppleTV2,1_5.1.1_10A831_Restore.ipsw
5.1.1 (ATV 3): AppleTV3,1_5.1.1_10A831_Restore.ipsw