root cause identified
@ -195,6 +195,7 @@ board = teensy20pp
build_flags = ${common.build_flags} -I $BUILDSRC_DIR
#board_f_cpu = 20000000L ; Bug in Arduino framework disallows boards running at 20Mhz
lib_deps = ${common.lib_deps}
lib_ldf_mode = deep+
src_filter = ${common.default_src_filter}
#