Manually added boards doesn't work in 1.8.5…?
Newer versions of the IDE (after 1.5) have a different folder structure where there is additional subfolders for maintainer and architecture.

&lt;Arduino sketch folder&gt;/hardware/&lt;custom name&gt;/avr/boards.txt


https://github.com/arduino/Arduino/wiki/Arduino-IDE-1.5-3rd-party-Hardware-specification