EspruinoWifi: InternalError: InternalError: Timeout on I2C Write Transmit Mode 2

Is your firmware up to date? (1v99) Looking at the error, the I2C peripheral appears to be having trouble getting a result after sending the device's address - which doesn't feel like it's an issue with the internal I2C interface.

You could try just calling I2c1.setup again, or maybe digitalWrite(...,1) for SDA and SCL pins and then setup again and see if that helps?

Could you try using software I2C and see if that helps?

var i2c = new I2C();
i2c.setup({sda:..., scl:...})

// ... then ...

i2c.writeTo(...)