a month later
5 days later

MetropleX Sorry, i meant if the previous OS is on a earlier version, before installing the the latest GOS, without updating the previous installation.

E.g. I had an android 12 on my phone installed the latest GOS, what is 13. On the surface worked fine... or i just thought?
Then
After the initilal "lets see, lets try", i reflashed again. Is this counts as a "from fresh to fresh" install now?

Meanwhile i might read about the "rollback protection", and some kind of shadow partition, what can help if the main stuff does not load in, but that can stuck on the previous flas' version, so that can cause problems... i am mixing stuff now..

a year later

The install guide explains this.

It's best practice to update the device before installing GrapheneOS to have the latest firmware for connecting the device to the computer and performing the early flashing process. Either way, GrapheneOS flashes the latest firmware early in the installation process.

The end result is the same, but having the latest firmware before flashing helps to avoid issues since the any known USB compatibility issues are already patched, etc.

  • N1b likes this.