Unfortunately, there is this GATT error. Which is a simple Bluetooth problem (unfortunately, we cannot control it).

We recommend that you start with a restarting the Bluetooth (power off and on), connect to your Monimoto in the app (app> settings> connect) and try to update the firmware again.

If this won't help, try this ->

Configuring the device in DFU mode:

Remove one of the batteries >
Wait 30 seconds >
Press and HOLD the button next to the SIM card (do not release it until the step where it is told to do so) >
Put the battery in >
Wait 2 seconds >
Release the button.

The red and green lights should blink together.

- // -

Now go to the Monimoto app home screen >
'Hamburger' menu in the upper left corner >
Right upper corner 'head' menu >
Restore firmware button >
There should be all possible Monimoto devices in DFU mode >
Choose the device to update