Hi,

I am trying to get back into the hobby after I crashed back in 2019. One of my ESC got burnt then, so I ordered a 4 ESCs (RobotDog 35A BLHeli32 ESC by FPV.Model), soldered them in place and left the quad in box until earlier this year.
In January I did a complete check of the quad, updated the firmware to 4.5.0, added ELRS to it.
Everything was connected and setup, went to arm but the motors wouldn't spin.

I first though it had something to do with the BLHeli32 firmware being 5 years old, and the FC being 4.5.0.
I tried:
1. Connecting to the ESCs using BLHeli32 Suite. It connects to the interface, but finds no ESC (see attached)
2. Checking the soldering with a multimeter - it was all right.
3. To narrow things down I removed 3/4 ESCs and left only 1 ESC connected to the FC (on PWM1 port).
4. I tried connecting to the ESCs with https://esc-configurator.com. Didn't get any result.
5. I tried BLHeli Configurator. No luck.
6. I tried BLHeli Suite 16.7.14.9.0.0 - SiLabs BLHeli Bootloader and got a "Erased or unknown firmware message (g)
7. I tried BLHeli Suite 16.7.14.9.0.0 - ATMEL/BLHeli SK Bootloader and got a "Found SiLabs ESC (expected Atmel) (g)
8. I tried BLHeli Suite 16.7.14.9.0.3 - SiLabs BLHeli Bootloader and got a "Found BLHeli_32 ESC (expected SilLabs) (g)
9. I tried changing the motor protocol in Betaflight - no luck
10 I tried using a different USB cable with no luck.

The interesting part is that i can spin the motor in Motor Test Mode both in Betaflight configurator and in BLHeli32 Suite.

2024-03-22 @15:58:52 -- Flight controller info, identifier: BTFL, version: 4.5.0
2024-03-22 @15:58:52 -- Running firmware released on: Jan 12 2024 14:10:22
2024-03-22 @15:58:52 -- Board: BRAINRE1, version: 0
ESC/Motor Protocol - DSHOT150
The battery is charged.
ELSR RX and TX are connected (I can see sticks moving in Betaflight).

Any thoughts on where should I look next?

Thank you!

If it is a BlHeli32 ESC you will need to use the configurator specifically for BlHeli32. Esc configurator and BlHeliSuite (for BlHeli S) will not work with the 32 ESCs as far as I know.
https://oscarliang.com/connect-flash-blheli-32-esc/

However if you are able to throttle up motors from BF motors tab, then likely you have a different arming issue. Do you have an arm mode mapped? If you go into the modes tab and flip the arm switch, you should see that mode light up. If that is working, and if you have a working OSD, it should display a message if anything is preventing you from arming. Otherwise check the status in BF configurator. Arming Disable Flags on the setup screen, or type status in the CLI.

I followed your advice and checked via OSD why it wasn't arming. Turns out it was because of no GPS lock.
I turned GPS off, it armed, but only motors 2 and 4 turned.

Which lead me to think there might be a wiring issue on the ESC side.
It turns out that even though the ESC had 2 pads on each side, only the GND was available on both sides, and the PWR was only on one side.

As i was fixing the last motor, I lifted the PWR pad, which solved the issue for good.

Thanks for your help!