Finding a direct, modern Android 1.0 ISO is difficult because the original Android 1.0 (released September 23, 2008) was designed strictly for early ARM-based mobile hardware like the T-Mobile G1. It was never officially released as an ISO for PC installation.
If you are looking to experience it for yourself, the best method is through the Android Studio archives. Android 1.0 Iso
(before it was Google Play), a physical-keyboard-centric UI, and no "pinch-to-zoom". While it lacks the bloatware-free efficiency Android One Finding a direct, modern Android 1