Troubleshooting

Problems resetting the board

After flashing the firmware via serial do a hard reset of the device (unplug & plug).
There is an issue with the ESP.reset() method. Check https://github.com/esp8266/Arduino/issues/1017 for more info.

Undefined reference to `__ieee754_sqrt'

FIX: You are using an old ESP8266 Core for Arduino

/home/odroid/.platformio/packages/toolchain-xtensa/bin/../lib/gcc/xtensa-lx106-elf/4.8.2/../../../../xtensa-lx106-elf/lib/libm.a(lib_a-w_sqrt.o):(.literal+0x8): undefined reference to `__ieee754_sqrt'
/home/odroid/.platformio/packages/toolchain-xtensa/bin/../lib/gcc/xtensa-lx106-elf/4.8.2/../../../../xtensa-lx106-elf/lib/libm.a(lib_a-w_sqrt.o): In function `sqrt':
/home/pi/xtensa/esp-open-sdk/crosstool-NG/.build/src/newlib-2.0.0/newlib/libm/math/w_sqrt.c:69: undefined reference to `__ieee754_sqrt'
collect2: error: ld returned 1 exit status
*** [.pioenvs/sonoff-pow-debug/firmware.elf] Error 1

This is due to a missing function in a core library (https://github.com/esp8266/Arduino/issues/612, not related to ESPurna). It will be probably solved with 2.4.0 version of ESP8266 Core for Arduino. In the meantime a quick fix is to replace the "(...toolchain-xtensa...)/xtensa-lx106-elf/sysroot/lib/libm.a" with the file one: https://files.gitter.im/esp8266/Arduino/Abqa/libm.a.tbz.

Wifi Stops

• First check you supply enough voltage to ESP8266. Not all power supplies are the same.

Unable to login to Web UI

• Use Chrome or Firefox browser.
• Safari and Edge may not work with the WebSockets Auth scheme Espurna uses by default
• Safari has a known issue requesting authentication twice: https://github.com/xoseperez/espurna/pull/1843#issuecomment-523435455

Unstable WiFi when using OpenWrt & mwlwifi

• Known issue with devices using mwlwifi (Linksys WRT32X, linksys 3200acm etc.): https://github.com/kaloz/mwlwifi/issues/278
  https://gitter.im/tinkerman-cat/espurna?at=5d961ada464b432fc1b2a4dd
  https://gitter.im/tinkerman-cat/espurna?at=5da87e7f65dd8569a0f30dd8
• Turning off WMM mode resolves the issue, switching WiFi to 802.11G mode

Custom build unstable when using specific router models

• Known issue with some older router models: https://github.com/xoseperez/espurna/issues/2104#issuecomment-574249525
• Adding -DPIO_FRAMEWORK_ARDUINO_ESPRESSIF_SDK221 to PlatformIO build_flags = ... will may solve the issue
• Arduino IDE provides a menu option for SDK version selection