Latest stable SD images should work flawlessly, although perhaps you need to use the testing branch, that includes some fixes for legacy v1 kits.
You simply follow these steps:
- Burn the latest SD image in a good enough SD card
- Boot and wait until the first-boot setup process has finished. As your display is not configured, you wont see anything. Let’s say you wait about 30 mins to be completely sure
- Connect your unit to your router (local network) using an ethernet cable
- access webconf on http://zynthian.local
- access hardware->kits and select kit v1 on
- access software->repositories, check testing and update
- Reboot
Regards,