! 症状

* (どのボードを選んでも)ビルド時に下記エラーが出る
 panic: no patch version found

! 原因

* platform.txt の version 記述の問題 (platform.txt が悪いか、ビルダが悪いかは不明)

! 修正法

 C:\Users\<USER>\Documents\Arduino\hardware\bitDuino10\avr\platform.txt
 内の
 version=1.6.x
 を
 version=1.6.3
 に修正

(修正内容は C:\Users\<USER>\Documents\Arduino\hardware\bitDuino13\avr\platform.txt を参考にした)

! 関連記事

* “Panic: No Major Version Found”
** https://forum.arduino.cc/t/panic-no-major-version-found/876644
* Arduino IDE 2.0 beta #215
** https://github.com/MCUdude/MightyCore/issues/215
** https://github.com/MCUdude/MightyCore/issues/215#issuecomment-837632957

""When a platform is installed to {directories.user}/hardware without a version folder, Arduino CLI uses the platform.txt version property to identify the platform's version.
""
""We are accustomed to be able to use previously defined properties within property definitions in the platform configuration files, and having those properties be expanded. However, this is not currently supported by Arduino CLI for the version field, which causes a panic when this is done due to the version not being parsable according to "relaxed semver".