Olimex ESP8266 flashing issue

[Mzojo]

I can’t seem to get Olimex ESP8266 to work with any example in VisualGDB. I currently have Olimex ESP8266-EVB that i have re-flashed using guide found on the Olimex website. The development bard is connected to the PC via Olimex USB-RS232 dongle and is powered trough the boards power jack with 5V (3.3V after onboard voltage regulation) laboratory power supply. After re-flashing the AT commands work and the device responds normally as expected.

Then i follow the example provided by VisualGDB website found here to flash the HTTP example to the ESP8266. The flashing process (press button, power cycle, press ok, “Programming Flash..”,) starts and completes successfully and enters the “debug” mode where it fails to find the device (the following GDB command is taking too long to complete: target remote \\.\COM9). Example projects do not work after flashing is completed (directly after fashing / power cycling / disconnecting dongle) and neither do the AT Commands.

Checking COM9 at 74880 shows that the device keeps crashing and resetting spamming the following:

load 0x3ffe8000, len 940, room 16
tail 12
chksum 0xc3
ho 0 tail 12 room 4
load 0x3ffe83b0, len 936, room 12
tail 12
chksum 0xfc
ho 0 tail 12 room 4
load 0x40100000, len 30536, room 12
tail 12
chksum 0x96
csum 0x96
OS SDK ver: 1.5.0-dev(950076a) compiled @ Nov  4 2016 19:29:32
rf_cal[0] !=0x05,is 0xFF

ets Jan  8 2013,rst cause:1, boot mode:(3,7)

I’ve been checking the forums and googling for the solution but cant seem to find anything. I’ve tried everything i thought of (reflashing different firmware at different flash sizes (dio, qio etc) but nothing works and I’m out of ideas. Does anyone know how i can fix this? Help would be greatly appreciated.

[support]

Hi,

Unfortunately the ESP8266/ESP32 devices are not very reliable and often behave unpredictably. We could quickly check if your firmware works with our Olimex ESP8266-EVB to see if the problem is in the board or in the firmware. Feel free to archive your project (with the binaries) and upload it to a file hosting so that we could check it.

[Mzojo]

Thanks for the reply. I’m double-checking now but i think i found the issue. i followed the tutorial slightly too blindly and set the SPI flash size to 4m where as EVB-ESP8266 has EX version at 16m. Project now flashing and working in debug mode. Still slight issue with behavior on power cycle (Does not work if not in debug) but that might be unrelated (possibly related to boot mode reverting to UART and not FLASH?). Double-checking and trying to fix the power cycle issue but at least I’m getting somewhere.

[support]

Hi,

If you are using the GDB stub, it will wait for the debugger to connect after each restart, i.e. the device won’t start without a debugger until you disable the gdb stub.

[Mzojo]

Ah! Thanks! Is there a way to use GDB stub just for flashing while the debugging + waiting for stub is disabled? I would rather not use J-Link if i don’t have to as i already use it flashing second MCU that will communicate with ESP in the future. Redoing connections every time i switch IC would be a major hassle. commenting out the “gdbstub_init()” seems way too simple to be true?

[support]

Hi,

No, that should be sufficient. VisualGDB will warn that the stub is not included and the debugging won’t work, but if you ignore the warning, the programming will still succeed.

You can also use the ESPImageTool.exe from the toolchain directory to program the binary directly.

[Mzojo]

Thank you for the help. Rechecked everything in the morning and it’s working great now. The thread can be locked / deleted now (or left, maybe it can help someone else in the future). Thanks again!

[Author]

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