Remote Serial Debugging ESP8266

I would like to know how to get remote serial debugging working with ESP8266 devices. Seems like there should be a way to make this work, but I haven't found it yet. When I start debugging VSCODE is trying to launch the elf file locally on my PC. What I want is for VSCODE to start the local GDB debugger. Below is my launch.json file. Is there something wrong in my launch file?

{
"version": "0.2.0",
"configurations": [
{
"name": "Launch",
"type": "cppdbg",
"request": "launch",
"program": "d:/dev/src/homeauto/sonoff/app/bin/esp8266/sonoff.elf",
"cwd": "d:/dev/src/homeauto/sonoff/app",
"miDebuggerPath": "d:/dev/arduino-1.8.5/hardware/esp8266com/esp8266/tools/xtensa-lx106-elf/bin/xtensa-lx106-elf-gdb.exe",
"MIMode": "gdb",
"setupCommands": [
{ "text": "file d:/dev/src/homeauto/sonoff/app/bin/esp8266/sonoff.elf" },
{ "text": "set remotelogfile d:/dev/src/homeauto/sonoff/app/gdblog.txt" },
{ "text": "set serial baud 115200" },
{ "text": "set remote hardware-breakpoint-limit 1" },
{ "text": "set remote hardware-watchpoint-limit 1" },
{ "text": "target remote com4" }
],
"externalConsole": false,
"visualizerFile": "d:/dev/src/homeauto/sonoff/app/.vscode/stl.natvis"
}
]
}

Start with the launch.json configuration in the issue, especially the cppdbg request, miDebuggerPath, setupCommands, and target remote com4 entry. Review the extension's remote-debugging behavior and determine whether the requested ESP8266 workflow is supported; done means the local GDB debugger can attach to the device without trying to launch the ELF locally.