Failed to start GDB server today

[magene]

I have a variety of projects I've been working on over the last year using a STM32Nucleo H7A3 board.. I use both the VisualGDB IDE and STM32CubeIDE.

I wanted to build a FatFs project from scratch using STM32CubeIDE yesterday and got it working surprisingly quickly. I powered down the Nucleo, pulled the uSD card and read it on my PC. The file was there with the right contents. I put the SD card back in the Nucleo and built the STM GPIO_InfiniteLedToggling example. It worked fine. I was putting some of the code from the LED example into my FatFs project and started getting a "Failed to start GDB server" error. All my STMCubeIDE project gave this error with slight variations. I tried some of the suggestions I found here and elsewhere on Google with no success. I figured I bricked the board somehow. Luckily I had another, new NucleoH7A3 board to use and everything worked again.

That was yesterday. Today the "Failed to start GDB server error" is back on the board I setup yesterday. The details are pasted below. I get a similar error when I try to run previously working projects in VGDB. I would really appreciate some help figuring out what I might be doing that is bricking my board and if there is some ST-Link utility (or other utility) that I can use to unbrick the board.

Thanks

[magene]

FYI - I seem to have found a solution. I downloaded the STM32Cube Programmer utility from the ST website. I was able to use it to connect to my bricked Nucleo with the Mode drop down selection in the ST-Link Configuration window set to "Power Down". That was the only Mode that worked. Once I was connected I could use the utility to download one of my previously working .bin files and everything worked fine. I've tried a few other project directly from Visual GDB using the normal build and debug workflow, no STM32Cube Programmer, and those project have worked fine also. Hope this helps someone else.

[Harvey White]

Normally what I use is the SWD mode. I've had problems when the debug settings under the IOC/debug are not set properly. I happen to use trace asyncnronous sw (not JTAG). If nothing is set, all bets are off.

[rpcy]

I'm now seeing that same "Failed to start GDB server" message, after having successfully downloaded and run dozens of revisions of my project code today. A google search led me here, but I do not understand either of the answers posted here. I have that Programmer utility but the only "Mode" button I can find on it doesn't have a "Power Down" option. I'm trying to use the standard SWD download mode; I don't know what IOC/debug means. I've tried 3 different Nucleo G491 boards and two different USB cables. I've also tried running a known-working project and it now encounters the same issue. I'm dead in the water and looking for any guidance, thanks...