diff --git a/Source/util.cpp b/Source/util.cpp
index af3209b9..922de28b 100644
--- a/Source/util.cpp
+++ b/Source/util.cpp
@@ -122,7 +122,7 @@ int update_bitmap(CResourceEditor* re, WORD id, const char* filename, int width/
   }
   fclose(f);
 
-  re->UpdateResource(RT_BITMAP, MAKEINTRESOURCE(id), NSIS_DEFAULT_LANG, bitmap, dwSize);
+  re->UpdateResourceA(RT_BITMAP, MAKEINTRESOURCE(id), NSIS_DEFAULT_LANG, bitmap, dwSize);
 
   free(bitmap);
 
@@ -201,7 +201,7 @@ void replace_icon(CResourceEditor* re, WORD wIconId, const char* filename)
   int i = 1;
 
   // Delete old icons
-  while (re->UpdateResource(RT_ICON, MAKEINTRESOURCE(i++), NSIS_DEFAULT_LANG, 0, 0));
+  while (re->UpdateResourceA(RT_ICON, MAKEINTRESOURCE(i++), NSIS_DEFAULT_LANG, 0, 0));
 
   for (i = 0; i < igh.wCount; i++) {
     fread(ige, sizeof(FileIconGroupEntry)-sizeof(DWORD), 1, f);
@@ -228,7 +228,7 @@ void replace_icon(CResourceEditor* re, WORD wIconId, const char* filename)
       throw bad_alloc();
     }
     fread(iconData, sizeof(BYTE), dwRawSize, f);
-    re->UpdateResource(RT_ICON, MAKEINTRESOURCE(i+1), NSIS_DEFAULT_LANG, iconData, dwRawSize);
+    re->UpdateResourceA(RT_ICON, MAKEINTRESOURCE(i+1), NSIS_DEFAULT_LANG, iconData, dwRawSize);
     free(iconData);
 
     fsetpos(f, &pos);
@@ -240,7 +240,7 @@ void replace_icon(CResourceEditor* re, WORD wIconId, const char* filename)
 
   fclose(f);
 
-  re->UpdateResource(RT_GROUP_ICON, MAKEINTRESOURCE(wIconId), NSIS_DEFAULT_LANG, rsrcIconGroup, sizeof(IconGroupHeader) + igh.wCount*SIZEOF_RSRC_ICON_GROUP_ENTRY);
+  re->UpdateResourceA(RT_GROUP_ICON, MAKEINTRESOURCE(wIconId), NSIS_DEFAULT_LANG, rsrcIconGroup, sizeof(IconGroupHeader) + igh.wCount*SIZEOF_RSRC_ICON_GROUP_ENTRY);
 
   free(rsrcIconGroup);
 }