doc/faq/a04-board-generic-is-unknown.rst
This error may pop up after switching between
staging <https://github.com/esp8266/Arduino#staging-version->__ and
stable <https://github.com/esp8266/Arduino#stable-version->__ esp8266
/ Arduino package installations, or after upgrading the package version.
.. figure:: pictures/a04-board-is-unknown-error.png :alt: Board nodemcu2 (platform esp8266, package esp8266) is unknown error
If you face this issue, you will not be able to compile any sketch for any ESP8266 module type.
Read below what is the error root cause or jump straight to the
resolution <#how-to-fix-it>__
The Root Cause
This issue is attributed to Arduino IDE Boards Manager not cleaning up
previous package installation before a new one is applied. As this is
not done, then it is user responsibility to remove previous package
before applying a new one.
To prevent it from happening, if you are changing between **staging**
and **stable**, first press *Remove* button to delete currently used
installation.
.. figure:: pictures/a04-remove-package-yes.png
:alt: If changing between staging and stable, remove currently installed package
There is no need to remove the installed package if you are changing it
to another version (without switching between staging and stable).
.. figure:: pictures/a04-remove-package-no.png
:alt: No need to remove installed package if changing its version
Depending on selected module the error message is slightly different.
For instance, if you choose *Generic ESP8266 Module*, it will look as
follows:
::
Board generic (platform esp8266, package esp8266) is unknown
Error compiling for board Generic ESP8266 Module.
Below is an example messages for
`WeMos <../boards.rst#lolin-wemos-d1-r2-mini>`__:
::
Board d1_mini (platform esp8266, package esp8266) is unknown
Error compiling for board WeMos D1 R2 & mini.
... and another one for `Adafruit Feather
HUZZAH <../boards.rst#adafruit-feather-huzzah-esp8266>`__:
::
Board huzzah (platform esp8266, package esp8266) is unknown
Error compiling for board Adafruit HUZZAH ESP8266.
If the issue already happens, then uninstalling and re-installing the
package with *Boards Manager* typically will not fix it.
Uninstalling and re-installing the Arduino IDE will not fix it as well.
Well, OK, fine. You will be able to fix it with Boards Manager. To do
so, you need to carefully go step by step through the effort of removing
new and then the old package. Once done you can install again the new
package. Did I mention that in between you need to change twice
`JOSN <https://github.com/esp8266/Arduino#installing-with-boards-manager>`__
in *Additional Boards Manager URLs*?
Fortunately there is a quicker and more effective fix. See below.
How to Fix it?
Issue resolution is as simple as deleting a folder with older esp8266 / Arduino installation.
Procedure is identical on Windows, Linux and Mac OS. The only difference
is folder path. For instance, on Mac, it will be
/Users/$USER/Library/Arduino15/packages/esp8266/hardware/esp8266.
Example below shows the path for Windows.
.. figure:: pictures/a04-arduino-ide-preferences.png :alt: Checking of Arduino IDE Preferences
.. figure:: pictures/a04-contents-of-preferences-folder.png :alt: Contents of Arduino IDE preferences folder
Arduino15\packages\esp8266\hardware\esp8266 directory. Inside you
will find two folders with different esp8266 / Arduino package
installations... figure:: pictures/a04-contents-of-package-folder.png :alt: Checking of contents of esp8266 / Arduino package folder
Note: If you are not sure which folder to delete, then remove both of them. Restart Arduino IDE, go to Tools > Board: > Boards Manager and install the esp8266 / Arduino package again. Select ESP8266 module and the issue should be resolved.
More Information
This issue has been reported quite frequently in
`Issues <https://github.com/esp8266/Arduino/issues>`__ section of
esp8266 / Arduino repository. The most appreciated solution was provided
by [@anhhuy0501](https://github.com/anhhuy0501) in
`#1387 <https://github.com/esp8266/Arduino/issues/1387#issuecomment-204865028>`__.
If you are interested in more details, please refer to
`#2297 <https://github.com/esp8266/Arduino/issues/2297>`__,
`#2156 <https://github.com/esp8266/Arduino/issues/2156>`__,
`#2022 <https://github.com/esp8266/Arduino/issues/2022>`__,
`#1802 <https://github.com/esp8266/Arduino/issues/1802>`__,
`#1514 <https://github.com/esp8266/Arduino/issues/1514>`__,
`#1387 <https://github.com/esp8266/Arduino/issues/1387>`__,
`#1377 <https://github.com/esp8266/Arduino/issues/1377>`__,
`#1251 <https://github.com/esp8266/Arduino/issues/1251>`__,
`#1247 <https://github.com/esp8266/Arduino/issues/1247>`__,
`#948 <https://github.com/esp8266/Arduino/issues/948>`__