If your GF30 Conical Fermenter, GCA (Glycol Chiller Adapter), G40, or G70 controller screen has gone blank during an update, this is usually down to a poor or weak WiFi signal.
What's likely happening
A firmware update needs a stable WiFi connection to complete. If the signal is weak or drops out partway through, the update can stall — which shows up as a frozen or blank screen.
How to fix it
- Leave the unit powered on and move it as close to your WiFi router as possible to get the strongest signal available.
- Let the update run — don't turn the unit off or interrupt it.
- Be patient. Firmware updates over WiFi can take a few hours or more to complete, especially over a weaker connection.
Still stuck?
If the screen is still blank after giving it time on a strong connection, get in touch with our Customer Support team with the following details ready — it'll help them diagnose the issue faster:
- Reboot check: if you turn the unit's power off and back on, does the screen briefly show the Grainfather logo and normal UI before going white again, or is it white the entire time?
- Connection history: before the screen went blank, were you able to successfully connect the controller to WiFi and control it via the app?
- If yes — had you updated the firmware to the latest version at that point?
- Your WiFi setup: Are you using any WiFi extenders? What's the distance between your modem and the unit? What brand/model is your modem?
- Grainfather account username
- Serial number
- Proof of purchase