sudomod

Hello, sorry to be a bother, but I bought one of Helder’s prebuilt lites, but when I turned it on for the first time, all I got was a white screen. Since I doubt it could be a soldering issue, what else could it be? I'm totally new to electronics so I could have messed something up but I followed along with the guide on YouTube so maybe I just missed something?

Using the correct SD card image? is the SD card inserted? I tested all pre soldered boards before shipping them.