[trust]

I recently purchased 4 of these flight controllers on ebay. I've bought a lot of these Atom flight controllers over the last few years and other than having to flash the latest firmware have not had much trouble with them. I have not purchased from this source before.
But these when plugged into my USB port with GCS on the firmware page it shows only a solid orange LED, and my PC doesn't recognize the USB port. Neither upgrade and erase or the Rescue process works - it never sees the USB device.
Is there anything else I can do to wake these up?

[TheOtherCliff]

For it to work with LP GCS, it must have an OP/LP bootloader on it.  The symptoms you describe are the same ones you have when it doesn't have a bootloader.  Of course it could be something else that is actually defective, but if all 4 have the same symptoms I would bet on a missing bootloader.

A few years ago there was a rash of cheap clone CC3D's being sold without a bootloader.

There is a procedure to install the bootloader.  It requires an "FTDI" (this is just the brand name for a common USB to serial adapter) and a hand made cable to go from the FTDI to the CC3D MainPort.  See the following 5 year old post for instructions:
https://forum.librepilot.org/index.php?topic=208.msg2503;topicseen#msg2503

CC3D was not tested with non-standard clone chips and so a code bug in a table that tells it how to talk to non-standard (but good and fully functional) flash chips (where the settings are stored) was not found and fixed until a few months ago.  I would install the firmware at this page to avoid the small chance of you fighting a "won't save settings" issue at a later date.
https://forum.librepilot.org/index.php?topic=4912.msg32933#msg32933

[trust]

Ok. I have an FTDI device so I hooked it up using pin 3 of the main port as Tx and 4 as Rx on the FTDI, connected to main port on the Atom (4pin) - also power pins. I shorted the Bl pin on the Atom. I know FTDI works as I used it for programming the OPOSD device.
Plugged in the FTDI device, which powers the Atom also (orange LED came on - orange seems to be in the place where the green LED is).
No blinking, just constant on.
I ran the STM32flash program with the ef_coptercontrol_1609.bin file - I got the enclosed error message after a few seconds. I did not see any transferring going on in the FTDI leds.
Is this the correct process? I tried reversing the TX/Rx pins - no difference.

[TheOtherCliff]

Well first thing, you have a while (I recall 60 days but better to check this yourself) to open a refund on eBay.  Don't let that run out...

Second, it may be that the program is too old for recent Windows, or that you need to do some permission thing (run as admin?).  I suggest that you try that archive.org page that is linked at the end of the page you just used.

Third, is that ebay seller still selling them?  Link? 

[trust]

Well, I looked up perhaps a new version of stm32flash,exe here:
https://sourceforge.net/projects/stm32flash/
And tried it - same result, slightly different error message - failed to init device.
I am using admin mode, so I don't think that is the issue, and I do see a tiny blip on the FTDI device when I run the program - so I think it is working - at least its getting to the FTDI device.
The ebay link is:
https://www.ebay.com/itm/OCDAY-Mini-CC3D-Combo-Atom-Nano-CC3D-Flight-Control-for-FPV-QAV-250-Quadcopter
I send them a message indicating the problem. Have not heard any reply yet.

[TheOtherCliff]

Next, I would try that archive.org page that uses the STM Flash Demo program.

[trust]

Can you send me the link again? I'm getting confused as to where to look. Thanks

[trust]

i downloaded the STM flash demo program and tried that. It sees the com port, but after I press next, it times out after 10s and says there is an error. Tried it also with swapped TX/Rx pins. Same result.

[TheOtherCliff]

Sounds like you already found it, but this forum page:
https://forum.librepilot.org/index.php?topic=208.msg2503#msg2503

links to this archive.org page which is a complete set of instructions for flashing the bootloader:
https://web.archive.org/web/20190701124058/http://www.southquay3d.com/index.php?route=news/article&news_id=9

[trust]

Thanks for the effort Cliff.
I applied for a refund, having made no progress with a solution, and they issued a refund today.
I ordered from a different vendor - hopefully these will work.