diff --git a/platformio.ini b/platformio.ini
index 47b90a5..cf490c6 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -9,7 +9,7 @@
 ; https://docs.platformio.org/page/projectconf.html
 
 [env:esp32dev]
-platform = espressif32
+platform = espressif32@3.5.0 ; <-- latest version sd R/W too slow!
 board = esp32dev
 framework = arduino
 board_build.f_flash = 80000000L