Download "USB Image Tool" and "WeTek Play rescue" files (you can use 7-zip to unzip them).
Plug a MicroSD to your PC using an adapter / card reader (backup anything on it because its content is going to be erased) and launch "USB Image Tool.exe".
You will see something like this:
1. As first thing select the removable disk that points to your MicroSD
2. Click "Add" button and navigate to the path where you extracted the rescue image and double click on it
3. Click "Restore" button and wait few minutes
Your rescue MicroSD has now been created, you can unplug it from your pc and insert it in WeTek Play's MicroSD slot (remove any USB peripherals eventually connected), and boot it with the usual "recovery trigger" combination.
After few moments you will see stock recovery doing its work and once it's done it will automatically reboot and you'll be able to enjoy WeTek Play again
To restore your MicroSD to its original capacity (I created a 512MB rescue image so now your MicroSD will be listed as a 512MB one) you can use SD Formatter choosing those options: "FORMAT TYPE -> FULL (Overwrite)" and "FORMAT SIZE ADJUSTMENT -> ON"
Note for Linux users:
On Linux you don't need any tool like "USB Image Tool" because every distro comes with "dd" command bundled.
Just plug your MicroSD to your pc and with a command like "dmesg | tail" see how your kernel names it (it can be something like "sdb" in case you have only one SSD/HDD installed or "sdc", "sdd", etc.).
Anyway, once you know what's your MicroSD card path (pay extremely attention to it or you might wipe important data if you choose the wrong unit), just type a command like "sudo dd if=/path/to/rescue.img of=/dev/sdc bs=512".
Actually the cool thing is that you can do the same using a spare WeTek Play (in case you own more than one unit): just insert the MicroSD in its slot, put the rescue image on a flash drive and plug it in.
Now, if you're using one of my custom rom builds your flash drive's content will be located under "/storage/usbdisk0", "/storage/usbdisk1" or "/storage/usbdisk2" (I did this to allow Android's vold to be able to mount at the same time up to 3 disks / flash drives, one per WeTek Play's USB port), just check with a command like "ls /storage/usbdisk0" where is located your rescue image and modify the dd command according to it.
Example: "su" (accept the eventual SuperUser / SuperSu prompt) and after that "dd if=/storage/usbdisk0/rescue.img of=/dev/block/cardblksd bs=512"