My dual boot postmarketOS - android shift6mq phone is broken

Preface : I’ve a shift6mq shift-phone that was running postmarketOS and Android in a dual boot (slot A/B) setup. Until yesterday… I rebooted my phone from postmarketOS to Android, and now I’m stuck in a fastboot screen . No more postmarketOS or Android :( How I got in this situation? Yesterday, I was using my shift6mq with sxmo/postmarketOS . Then I rebooted to Android using the script below, like…