DS D9

FCC ID 2AEMN-D9

Also known as Lenovo HW02

When I was figuring out DFU update I modified firmware version number strings in DS-D6 firmware to lower numbers to force the app to find OTA update. This worked perfectly and confirmed that OTA package is just standard Nordic ZIP made by nrfutil, however after the app succesfully downloaded and updated firmware over bluetooth the clock display was wrong. The app still connected, button on watch worked however I also noticed bluetooth device name changed to DS-D9! One of version numbers was actually model number and by lowering it I changed model from DS-D6 to DS-D9.

Since this DS-D9 was apparently very compatible with DS-D6 I searched for it and finally found it on aliexpress for $11.99 (which was kind of lucky as now I can't find it below $20 which is IMO too much for such poor visibility small OLED, search terms - "mpow fitness" or "lenovo hw02")

Differences:

• SSD1306 OLED resolution is 70x40
• HR sensor is HRS3300 according to strings in firmware that works (it is AMS7000 in latest stable DS-D9 firmware but that one fails to show heartrate in mine)
• D2 pin (charging voltage/detector) is not analog but digital, D3 (battery voltage) is still analog