diff --git a/platformio_override_sample.ini b/platformio_override_sample.ini
index 22256f679..f85ce989f 100644
--- a/platformio_override_sample.ini
+++ b/platformio_override_sample.ini
@@ -52,6 +52,11 @@ build_flags               = ${core_active.build_flags}
 ; set CPU frequency to 80MHz (default) or 160MHz
 ;board_build.f_cpu         = 160000000L
 
+; set Flash chip frequency to 40MHz (default), 20MHz, 26Mhz, 80Mhz
+;board_build.f_flash       = 20000000L
+;board_build.f_flash       = 26000000L
+;board_build.f_flash       = 80000000L
+
 ; *** Upload Serial reset method for Wemos and NodeMCU
 upload_port               = COM5