I have just tried to update the firmware in my V2 Plus 4 to the latest version (20220814) using VNA_QT in Windows 11.   The VNA showed up as COM7 in QT and I pointed to my downloaded firmware bin file and started the process.  My VNA screen went completely white and it is unresponsive.  I have tried turning it on again whilst pressing the left hand button but this has no effect.  The VNA no longer shows up in QT.  Win11 Device Manager - Universal Serial Bus Controllers - reports "Unknown USB Device (Device descriptor request failed)"
Is there a way of forcing a hard reset into DFU  mode?  On the back of the LCD board, along the connector strip, there is the word "TOUCH" and white lines pointing to T_IRQ and T_CLK.  I wonder if this is used to produce a hardware reset but I want to be sure before causing further problems :-(

Any help gratefully received, thanks., Russ