Dub Echo - suddenly not working (XDJ-RX2)

Hi,

The dub echo effect suddenly stopped working for me. However, the other effects still work (sweep, filter, noise).

I tried to update my firmware just in case that was the issue (downloaded it, put it on my USB and followed the firmware update instructions), but the screen would freeze as soon as it asks me to "Connect USB storage device to USB port 1" (I inserted my USB but it wouldn't start updating). I currently have version 1.37 and was trying to update to 1.38.

Not sure what the issue is for the Dub Echo -- or if it's related to the firmware. Any help would be appreciated. Thanks