Working USB wifi adapter now not being detected

I’ve been successfully using RT5370 chipset wifi USB for several months on by BBB running debian 3.8.13-bone68 with no issues whatsoever.

Recently however when booting the device from power off state the USB adapter is no longer detected. “ifconfig -a” doesn’t not show any wlanx devices, lsusb does not list the usb adapter at all.

If I ssh into the device and issue a reboot command then the USB device is detected.

If I plug in a new USB adapter (after clearing out /etc/udev/rules.d/70-persistent-net.rules) into powered off device it correctly detects the new usb adapter from power off startup.

Connected the ‘non-working’ USB adapter into a different BBB running the exact same setup (they are identical s/w clones) works fine.

I am a little stumped and am not sure if there is another file besides “/etc/udev/rules.d/70-persistent-net.rules” that I should look at - would appreciate ideas/feedback.

Is there any way to manually scan for usb adapter for fault finding - seems only way to detect device is to reboot?

Colin