Dovado TINY overwrite OEM stock FW

Hello, i have a question regarding this explicit device. Dovado TINY

i want to be able to run, OpenWRT on this, the device, is's currently running firmware 7.3.21 , i used the firmware update utillity downloaded from Dovado in order to make the update.. i was able to update the same file from within the stock firmware HTTP GUI - Upgrade tab. To my question, when i try to update - write OpenWRT firmware i get a error message

Input file is in incorrect format
Please make sure that you have selected a BIN file downloaded from
If you have downloaded the Firmware Utility, please run it by double-clicking on it instead of selecting it here.
You will not need to restart the system.

The file i been trying to write is



Am i doin'g something wrong here, using the wrong file? I been searching for google and trying to read in both reddit and the forum here which file and how to write it. - Is it mandatory for me in order to proceed writing this firmware, that i must use FTP server in order to achive this? More concretely what is required for me in order to write OpenWRT to this device?

Thank's in advice