HY-08 (Non-Wifi and Non-STM)

[zaifkhan]

Hi, I have a version of the HY08 thermostat labeled as HHD-HY08-1MB_WE3_V12_TWT. They resemble the ones in this thread: https://community.home-assistant.io/t/convert-dumb-thermostat-into-a-smart-one-hy08/497105

I tried to use the ESP12S with the HY08 binary only to realize that the chip is not an STM chip but something labeled as 1721 with a TM1621 LCD controller. Has anybody come across something similar? How would I convert these to Wi-Fi (as the vacant pads with solder point at some support for a wireless version)?