I have an Olimex MOD-WIFI-ESP8266-DEV which I have worked on for over a week using GDB stub debugging. Today I was doing a final test that involved calling SDK function system_restore() to erase WiFi credentials that are stored after a successful smartconfig.

After doing this I am unable to debug in VS. Flashing the chip works but that is about it. VisualGDB reports unable to connect to GDB stub after hanging for a while. Here’s the last part of the error:

-gdb-set disassembly-flavor intel
^error,msg="No symbol \"disassembly\" in current context."
-gdb-set print demangle off
^done
-break-insert -f main
&"Function \"main\" not defined.\n"
^done,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="<PENDING>",pending="main",times="0",original-location="main"}
Warning: could not set a breakpoint on main. 'Step into new instance' will not work.
-break-delete 1
^done
Found an SPI FLASH section at 0x00010000. This image is a non-OTA image.
set serial baud 74880
&"set serial baud 74880\n"
=cmd-param-changed,param="serial baud",value="74880"
^done
target remote \\.\COM8
&"target remote \\\\.\\COM8\n"
~"Remote debugging using \\\\.\\COM8\n"
~"Ignoring packet error, continuing...\n"
&"warning: unrecognized item \"timeout\" in \"qSupported\" response\n"
~"Ignoring packet error, continuing...\n"
~"Ignoring packet error, continuing...\n"
&"Bogus trace status reply from target: timeout\n"
^error,msg="Bogus trace status reply from target: timeout"
-target-disconnect
^error,msg="You can't do that when your target is `exec'"
-gdb-exit
^exit

What’s more, the ESP doesn’t run the code and when rebooted via a button it spits out this on the serial.

ets Jan  8 2013,rst cause:2, boot mode:(3,6)

load 0x3ffe8000, len 916, room 16 
tail 4
chksum 0x9e
load 0x3ffe83a0, len 1084, room 4 
tail 8
chksum 0x3f
load 0x40100000, len 30828, room 0 
tail 12
chksum 0xab
csum 0xab
ŒâÜ[00]ìx[02]‚nÀä>[12]rÜØònãb[0C][18]’[0C][1C]žl`[1B]Äœ„’œÃ[02]„ØbŸ[03].... (<-3 lines of garbage)

I tried every suggestion in this older thread to no avail: https://sysprogs.com/w/forums/topic/esp8266_thing-failed-to-connect-to-the-gdb-stub/

I also tried the IoT HTTP server example code unmodified and it too fails to run.

Suspecting a broken chip I then tried making a short test Arduino program and flashing the binary but to my surprise this worked fine. A string that is printed out in a loop with some delay in between comes out clean in the terminal window.

At this point I am completely stumped. Nothing in my hardware or software config has changed and nothing in the code either. Just this single invocation of system_restore() (via a push button signal) and my whole project blows up. The most worrying thing is that the code flashed via VisualGDB doesn’t even run. To verify that the chip is running I’m using a 5 seconds interval timer which prints a short message (os_printf()) but as of today, this doesn’t happen anymore. If it was a baud rate issue I’d expect to see some garbage characters printed out periodically but instead I only have complete silence.

Any suggestions on what more I can do to find the cause of this problem would be highly appreciated.

• This topic was modified 6 years, 9 months ago by parsec67.
• This topic was modified 6 years, 9 months ago by support. Reason: formatting