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stuff for Desay/MPOW DS-D6 nRF52832 bracelet
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espruino Update Jun 5, 2019
fwdump fixed botloader - version with no arrow animation Jun 5, 2019
micropython Update May 24, 2019
photos 72x40 OLED test on DS-D9 Mar 7, 2019 Update Jun 17, 2019


Custom Espruino/Arduino/Micropython firmware for Desay/MPow DS-D6 nRF52832 bracelet

Also works on Mpow DS-D9/Lenovo HW02 and Lenovo HX03W with minor changes.

Where to get the device

I got it from GearBest In recent months it is quite often on sale (lowest so far was $6.99). The price changes often (sometimes even multiple times per day) so if it is for full price you may try to wait few days (or hours). Sometimes the discount is only valid in their mobile app. You can also try to use MPOWDS-D6 promo code at checkout if it makes a difference. Previously it was also avaliable in various other places like ebay but it is quite old device so nowadays it may be hard to find elsewhere. Gearbest may be the last one and once the stock runs our it may be the end.

HW reference

DS-D6 FCC info

Direct links to internal photos


  • all/most hardware known and documented (HR sensor somehow works but I don't use it)
  • it is possible to update and restore device via bluetooth or TTL serial without opening it as long as your app is developed with Nordic SDK11 and SoftDevice 2.0.x
  • recent build of Espruino works with all hardware with no issues, flashable DFU package here
  • it is also possible to update device to newer version of SDK, bootloader and SoftDevice without opening it (and also restore it back) so porting SW that requires higher SDK and SoftDevice versions is now possible too (e.g. micropython). This involves flashing patched original bootloader first as there was bootloader bug preventing the upgrade to newer SoftDevices.
  • build of Adafruit bootloader available with latest version of S132 softdevice so both latest Micropython and Adafruit Arduino Core for nrf52 is easy to use. See micropython folder.

All stuff documented in WIKI

For contact use either github issues here or join or Espruino forum.

Initial progress (for historic reasons) here

Firmware in fwdump folder was dumped via gdb over SWD as seen below (using bluepill board flashed with blackmagic probe firmware). Restoring over SWD works.

(gdb) info mem
Using memory regions provided by the target.
Num Enb Low Addr   High Addr  Attrs 
0   y      0x00000000 0x00080000 flash blocksize 0x1000 nocache 
1   y      0x10001000 0x10001100 flash blocksize 0x100 nocache 
2   y      0x20000000 0x20010000 rw nocache 

(gdb) dump memory dsd6-flash.bin 0x00000000 0x00080000
(gdb) dump memory d6d6-uicr.bin 0x10001000 0x10001100

Other devices made by Desay


There is similar bracelet without HR sensor - Lenovo HX06 (lowest so far for $11.99). It is made by same manufacturer and shares app and the watch UI look&feel is the same. Also the FCC info seems promising - CPU marking is unreadable but board looks very similar to DS-D6 and there are SWD test points (= ARM Cortex M architecture) so I ordered that one too. UPDATE 7.12.2018 sadly after receiving it I found HX06 is not Nordic based but has Dialog DA14585/6 chip There is SDK available from Dialog however the chip architecture is not suitable for large codebase like Espruino. There is 96KB of SRAM for both data and code, code is mirrored at poweron from SPI FLASH to SRAM, there is no XIP (execute in place) for flash memory like there is e.g. for ESP8266 or NRF52840 so everything (code,data,bss) must fit into that 96KB SRAM. However for Arduino C coding it should be good enough and the device is quite hackable. USB data pins have serial port too and DA14585 documentation says the device could boot directly from serial port just like from SPI flash so it may be in a way unbrickable. I have atached SWD debugger and dumped SRAM so there is plenty of information how to proceed. If you would like to continue with this let me know. The OTP memory is empty so it runs in developer mode with nothing locked.

HX03, HX03W, HX03F (a.k.a. DS-D10,10W,10F)

These are three similar nRF52832 based models with same HX03 FCC ID duplicated also as DS10. HX03W and F are available e.g. on Gearbest ($21, $17) or Banggood (had flash sale of HX03W for $9.99). Bangood has also the third HX03 device (with no W or F). This looks almost like HX03W but has only 128x32 LCD like DS-D6 so it is the worst of those three, so make sure you are not getting this one by mistake.

I have ordered couple of HX03W ones. Will update once I receive it. According to Desay DS-10(W/F) firmware DFU zips these are also SDK11 based so everything should be very similar to DS-D6. UPDATE 31.05.2019 I got it and almost all stuff is same (button, motor, serial on USB data pins, charging voltage, KX023) as DS-D6 except display and HR sensor, still figuring out those. However same DS-D6 Espruino build runs just fine. Also DS-D10W unbranded firmware runs on this HW (but have less functionality than Lenovo branded one).

DS-D9 (a.k.a. Lenovo HW02)

HW is very similar to DS-D6 to the point that D9 firmware runs on D6 only with garbled display (clock digits are cut off). FCC info I have ordered one from Aliexpress for $11 (search for "mpow fitness"). This one has smaller OLED positioned horizontally and is charged via cable so it should be thinner. There are still 4 pins including serial port. I hope the same Espruino binary for DS-D6 will run 'as is' on D9. UPDATE 4.3.2019 I got it and it is indeed exactly the same except the display which is 72x40. All the pins seems to be wired in same way (motor, spi display, battery, serial) and flashing same DS-D6 espruino binary over serial worked just fine. So while DS-D9 is even harder to get and the OLED has poor visiblility and resolution, I still like its minimalistic design a bit more than DS-D6. See also wiki page.

Lenovo HW01 (Desay B521)

This one is very similar to DS-D6. I managed to get firmware file for HW01, flashed it to DS-D6 and it works except display being unreadable. This means it is same architecture as others and should be usable too. If you have one and want to experiment with custom firmware, let me know.

Other nrf52832 Desay models

Devices mentioned above, while still being sold, are no longer manufactured by Desay OEM manufacturer, however there are more current models they offer. They are suppored by MPOW android app and we have links to beta firmware downloads. They still look like newer iterations of same SW and HW design. Names are DS-D15F, DS-D20F (also FCC ID), DS-Z10F So far I didn't find them available for sale via some brand like Lenovo or MPow.

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