I could not find historical IPSW versions for the first revision of the 7th generation iPod nano, so here they are.
The following is based off of archive.org's copies of the iTunes initialization plist.
| Version | Build | URL |
|---|---|---|
| 1.0.4 | 37A40005 | iPod_1.0.4_37A40005.ipsw |
| 1.0.3 | 37A30172 | iPod_1.0.3_37A30172.ipsw |
| 1.0.2 | 37A20067 | iPod_1.0.2_37A20067.ipsw |
| 1.0.1 | 37A10002 | iPod_1.0.1_37A10002.ipsw |
It does not appear that firmware 1.0.0 was made available (or, perhaps that it was ever captured by archive.org).