Imp not connecting any wifi

I bought 4 imps, 3 of which connect fine, the forth is deciding to be difficult.
It will accept the blink up but then just flash red of trying to find WiFi, or if using the wps system it will flash to detect but never get registered. I’ve tried on multiple networks with various security with no luck.
Is there a way of either flashing the drive to factory reset or directly accessing the log info when not online as I need to know what the problem is to fix it. Otherwise this might be somehow a dead WiFi connection and need replacing.

Thoughts anyone?

Can you give the mac address of the one that isn’t connecting? Are they all being used in the same april board? (ie could the problem be a power supply one in the host board?).

Do you get the WPSing flash code after blinkup?

Yes I’ve used the same april board without success, and the lights were flashing in the correct manner for detecting the wps connection, (green red green) as the other ones that were successful.
Why do you need the Mac? I don’t have it on me at the moment but I can post later.

Just want to see whether it has ever connected and what SW version it was running at that point.