diff --git a/extras/mcufriend_how_to.txt b/extras/mcufriend_how_to.txt
index af7f937..2b88273 100644
--- a/extras/mcufriend_how_to.txt
+++ b/extras/mcufriend_how_to.txt
@@ -118,8 +118,15 @@ It also runs on NUCLEO-F103 and TEENSY3.2 with Sparkfun Adapter
 18. Please run LCD_ID_readreg.ino to verify your non-standard wiring.  Paste the defines to a Forum message.
 
 19. OPEN-SMART Shields have different wiring to regular Uno Shields:
-    Edit mcufriend_shield.h:  #define USE_SPECIAL
-    Edit mcufriend_special.h: #define USE_OPENSMART_SHIELD_PINOUT
-    Edit MCUFRIEND_kbv.cpp:   #define SUPPORT_8352B
+    Edit utility/mcufriend_shield.h:  #define USE_SPECIAL
+    Edit utility/mcufriend_special.h: #define USE_OPENSMART_SHIELD_PINOUT
+    Edit MCUFRIEND_kbv.cpp:           #define SUPPORT_8352B
 
+20. OPEN-SMART Shields can not read LM75A on a Mega because there are no SDA/SCL pins next on AREF header.
+    Uno:  LM75A on pcb works.  Difficult to add external I2C devices when Shield is plugged in.
+	Uno:  All use of SPI bus should use SPI.beginTransaction(), SPI.endTransaction()
+	Leo:  I do not support USE_OPENSMART_SHIELD_PINOUT_LEO
+	Mega: Old boards do not have SDA/SCL on AREF header.   Only external I2C devices on COMMS header
+	Due:  MAX809 Reset chip interferes with 3.3V RST on SPI header.  Manual reset for Upload / Run.
+	
 CHANGE HISTORY: is now in "mcufriend_history.txt"