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Guide to update the Firmware of the No.1 Sun S2
Date2015/7/17 12:43:57

The No.1 Sun S2 smartwatch has just been released and No.1 is already offering firmware upgrades to their first circular watch. In this post, I will explain step-by-step how to upgrade the firmware of your No.1 Sun S2.

First of all, here’s a disclaimer: I am not responsible for any possible damages to your device while upgrading the firmware. Flashing a new firmware always contains the risk of breaking your device, making it unusable. Although unlikely, there can be always a small risk to brick your device, resulting in a permanent error. If you are not sure whether you want to take this risk or are completely unaware of flashing steps, I recommend you not to continue.

Read the above carefully? Still want to continue? Good :). So let’s go. What do you need?
-No.1 Sun S2 Smartwatch
-The Sun S2 USB connector and a microUSB cable
-An USB Port

1. First of all, download the latest firmware for your Sun S2. You can find it here.

2. After downloading, extract the .zip-file.

3. Open the “2502 firmware update tool” folder.


4. Open “Flash_tool.exe”.

5. Click on “Options” and make sure the “USB Download/ReadBack (Data Card)” is checked. Then click on “Format FAT (Auto)”.


6. Make sure the third option “Format FAT” is checked.


7. Back in the main menu, click on “Scatter/Config File” and navigate to the .cfg file of the downloaded fimware. It should be in “EXTRACTED_FOLDER/T2_S2_LANGX_XXXXX/T2PCB01_XXXXX/”. EXTRACTED_FOLDER represents the folder you extracted the .zip file in, while the X’s can be different numbers or letters. Afterwards, the Flash Tool should look similiar to this:


8. Power off your No.1 Sun S2. Put it on the USB connector. Don’t connect the USB connector the the PC yet.

9. Click on “Download” in the Flash Tool. Does it show an error similiar to e.g. “Can not connect to certain COM Port”? If yes, continue here, if not jump to step XX.

10. That means the drivers are not installed yet. Close the Flash Tool and go to the folder “drive” in the main folder and install the drivers by launching the “InstallDriver.exe”.


11. After successfully installing the drivers, make sure you closed the Flash Tool. Plug in the powered off smartwatch and after a short time your PC should recognize the watch and should see it in the explorer. Thenunplug the watch again from the PC.

12. Start again the Flash Tool program, the settings should be saved. But to be sure, check steps 5 to 7 again.

13. Click on “Download”.

14. Make sure the USB connector sits tight on the Sun S2. Connect the powered off No.1 Sun S2 to the PC. Leave it in a stable position, since the USB connector can easily lose connection. Losing connection while flashing the preloader results in a broken device.

15. The Flash Tool starts flashing now. It takes around 2-5 min.

16. If it succeded, a window with a green circle should pop up. Congratulations, you just upgraded your smartwatch :)!

That was it, I hope it worked for you as well :).