OTA update error 500

Running 0.15.3 on a Dig-Octa Brainboard. Decided it would be good to update to 0.15.4 before starting a major rewire. It fails with error 500. Online suggestion that disabling relay control may facilitate OTA, so I tried that with no change in behavior. I don’t want to start a big task with an unstable solution. Open to all suggestions.