OpenEVSE WiFi V1 - Update stuck on 97%

I tried to make an update to my OpenEVSE WiFi V1 to V4.2.2 via webinterface, but the EmonEVSE display got stuck on an indication saying that the WiFi update was at 97%. It was like that for hours and then I rebooted the EmonEVSE and now I have no WiFi access.
How can I flash the ESP32 now?

This is the module: OpenEVSE WiFi Gateway V4.x - Shop | OpenEnergyMonitor but with a different configuration (see photo)

Have you flashed the partition on your new board first time? This is 16mb flash boards, not sure how they were partitioned at factory.
We still use for now old partitioning scheme like 4mb modules.

You should starts from scratch flashing with the serial adapter

I used the web interface from the OpenEVSE to perform the update.
I guess that now I have to take the wifi gateway out and flash it using a USB Serial Programmer. I will check the link you posted to see how to do it.