Modules with STM32F103C8 MCUs are not supported in release builds (e.g. URUAV TMX5, VANTAC, etc.)

[pascallanger]

This module is using wrong components with the majors being:

• STM32 with 64KB of flash (STM32F103C8) instead of 128KB (STM32F103CB)
  
• NAND (C00) instead of XOR (C86) affecting telemetry
  

If you have purchased this module, you should go back to your reseller and claim your money back since the hardware is not matching the description (64KB vs 128KB).

[ozonisator]

I can confirm that this also applies to the URUAV TMX5 Lite variant. Same MCU, same flash :(
Can you elaborate how the NAND flash is affecting telemetry? I had some really odd problems with the TMX5 lite and a FrSky D4R-II receiver. Range test was fine but when flying (~10m ) I lost control for about 3 seconds, no "telemetry lost" or "RSSI critical" warning from my radio. Happened multiple times. I am using the current v1.3.1.49 build, the module came with a really old version (1.2.xxx).

[kilrah]

NAND flash

Nothing to do with flash, just a logic gate that's supposed to invert the telemetry signal but isn't the correct type.

[ozonisator]

Never mind, must have been all that LiPo smoke exposure after digging the burning battery out of the ground ;-D

[pascallanger]

The STM32 on the TMX5 is most likely able to go above the 64KB limit that the manufacturer indicates in the datasheet. While it can store up to 128KB which you are writing with the current Multi tooling, we've seen these modules having erratic behaviors which shows that the flash is not reliable above the 64KB... Just think about it, the components which have a full good flash are sold as128KB the others at 64KB, this is how things work.
Now if you want to fly with it, it's your take but personally I won't take the risk...

[ozonisator]

It's not worth the risk, too bad I stumbled across this issue after wrecking my copter. However, the TMX5 module has so far been working fine for indoor flying, no problems with flysky and frsky D8/D16. Really awesome experience. It may have been a faulty PPM wire that caused my initial problems. That would explain the failsafe event without "low RSSI/telemetry lost" warning from my radio. Since I got my money back I am going to try to replace the STM32 with the proper STM32F103CBT6.

[pascallanger]

Vantac Lite modules are also affected by the wrong STM32 chip, added to the subject.

[iz3man]

Could you please clarify that to me? I purchased this module https://www.banggood.com/URUAV-TMX5-4-IN-1-A7105-CC2500-CYRF6936-NRF24L01+-Multi-Protocol-Transmitter-Module-Compatible-FrSky-X9D-X10-Transmitter-p-1525898.html?
And it claims to be MCU: STM32F103CBT6(128K ROM, 20K RAM)
Arrived today, and I wanted to upgrade it just to see the NEW NOTE that it's not supported (anymore?).
I opened it up, but to be honest I can't say if this is a 'B' or an '8'. How do I find out?
Thanks

Made this pic. It's hard to make it as large as possible. I really can't say ....

[benlye]

That's a C8. The B has a single straight line down the left hand edge.

Your best option is to return it as it is not what they claim it to be and purchase the iRangeX IRX4 Lite

[benlye]

For comparison, here's a photo of the STM32F103CB in my IRX4 module. Once you know what they look like, the 8 and the B become easier to distinguish.

[iz3man]

Thanks for clarification and F*CK. :(
Btw: Would it be ok to swap the chip for one of these? https://www.aliexpress.com/item/4000113089300.html?spm=a2g0o.productlist.0.0.48c62f0d0BZCPo&algo_pvid=4c39b621-2f79-4f24-a4fc-416eea8f138a&algo_expid=4c39b621-2f79-4f24-a4fc-416eea8f138a-2&btsid=0b0a050116016613800332457ea3fd&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

I never had a claim with BG, but shipping already was a disaster. I guess it would be a hard fight.

[iz3man]

Or maybe sacrifice one of these STM32 developer boards? I got two here and they show the very same chip as in the picture you posted.

[pascallanger]

If you are able to replace the STM32 by the CB version then yes it's all good. I won't be able to do it personally as it's so small but if you can then sure it will work.