SimToo XT175: we have to try!

Hi, I have received the infamous Simtoo XT175.

This drone has great potential in my opinion, it definitely needs a firmware upgrade and in any case an accurate vision and calibration of some parameters.

Now I’m not an APM Planner expert, and don’t know where to start for the firmware.

I connected the drone via USB to a macbook and I started APM Planner 2.0.27-rc1, the software recognizes the drone and connects. Detect many parameters, from the logs I extracted the firmware version of the drone:

ACSimtoo V3.2.2I Mini Jul 19 2018

Surely it is a custom version of ArduCopter, unfortunately it has never been updated (there is a version around the net that does not seem to correct its problems).

Basically it has this problem:

  • Failsafe mode which is triggered very often even if the conditions are not met
  • Bad heading error

I hope someone can help me with the development and recovery of this drone, we would really do a favor to many enthusiasts who have bought it

P.S. sorry for my english, i’m italian :slight_smile:

Ardcopter 3.2.1 is the last version that supported the old APM Flight Controller so I suppose it’s a version of that FC. And you could be right about a custom version as there was no 3.2.2 official version. There may not be much you can do. What does the Flight Controller look like?

This is the controller

The Flight Controller in the craft that is running Arducopter. If you happened to have it apart…

ok i have to open the copter, tomorrow i’ll try. Thanks!

Photos from internet:



dkemxr i see that 3.4.6 also support apm1, i suppose this is the old controller you mentioned.

UPDATE: inside the folders there is the old firmware :frowning:

3.2.1 is the last Arducopter version that supported APM hardware. You can see this in the changelog.

I am curious about the datalink radio module. Could you please find it out and let me know the chip’s brand?

I’m looking into this too.
bit of info to add to the topic.
below is a screen shot of the port scan. port 50000 you can connect to mission planner via TCP over wifi
I’m guessing port 7070 is the video stream but I’m struggling getting anything form it. - it may be password protected feed I’ve tried wireshark but cant get any info
Screenshot 2020-12-30 203349

ok i’ve opened the copter:

The chip is erased :frowning:

On the back i see “x665_v2.0 TOPSUNSHINE”

Atheros is probably the wifi chip…

Camera Module, is actually linux board with wifi and decent camera

Marked Atheros AR1021X-CL3D, 2.4 to 5.8GHz 2T2R WiFi Module
With this price, this drone is very valuable for diyers like me :grin:

Application Processor, name already sanded
But after android reverse engineering, i assumed this Allwinner MR100
You can find more detail in Here and Datasheet

  1. GND
  2. RX (3.3V)
  3. TX (3.3V)
  4. VCC (5V)

Hi @pendekar,
I have a “bricked” Simtoo XT175 linux board that I try to recover. I got USB connected and “working” on the DM and DP pins, but fail to enter FEL mode with all ways I could find (SD FEL boot image, short CL on NAND etc.). So, I try to dig into the MR100 datasheet, but your link isn’t valid anymore. I could only find general info here but no datasheet: MR100-breif -20210204 (
Do you have an alternative datasheet link?