diff --git a/win32/customactions.cpp b/win32/customactions.cpp
index 783cf24d..f2d9ad41 100644
--- a/win32/customactions.cpp
+++ b/win32/customactions.cpp
@@ -63,6 +63,11 @@ typedef struct _MD_REGISTRATION
 /* note: we could have added the minidriver registration data directly in OpenSC.wxs but coding it allows for more checks.
 For example, do not uninstall the minidriver for a card if a middleware is already installed */
 
+/*
+ * In order to compute the proper ATRMask, see:
+ *   https://github.com/OpenSC/OpenSC/wiki/Adding-a-new-card-driver#windows-minidriver-support
+ */
+
 MD_REGISTRATION minidriver_registration[] = {
 	{TEXT("ePass2003"),                       {0x3b,0x9f,0x95,0x81,0x31,0xfe,0x9f,0x00,0x66,0x46,0x53,0x05,0x01,0x00,0x11,0x71,0xdf,0x00,0x00,0x03,0x6a,0x82,0xf8},
                                           23, {0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff}},