diff --git a/reactos/include/wine/cfgmgr32.h b/reactos/include/wine/cfgmgr32.h
index e29063acb1b..e7d036fc63a 100644
--- a/reactos/include/wine/cfgmgr32.h
+++ b/reactos/include/wine/cfgmgr32.h
@@ -36,13 +36,16 @@ typedef CHAR  *DEVINSTID_A;
 typedef WCHAR *DEVINSTID_W;
 DECL_WINELIB_CFGMGR32_TYPE_AW(DEVINSTID)
 
-
 #define CR_SUCCESS             0x00000000
 #define CR_OUT_OF_MEMORY       0x00000002
 #define CR_INVALID_DATA        0x0000001F
 #define CR_INVALID_MACHINENAME 0x0000002F
 #define CR_ACCESS_DENIED       0x00000033
 
+#define MAX_CLASS_NAME_LEN  32
+#define MAX_GUID_STRING_LEN 39
+#define MAX_PROFILE_LEN     80
+
 
 CONFIGRET WINAPI CM_Connect_MachineA( PCSTR, PHMACHINE );
 CONFIGRET WINAPI CM_Connect_MachineW( PCWSTR, PHMACHINE );
diff --git a/reactos/lib/setupapi/devinst.c b/reactos/lib/setupapi/devinst.c
index 30f8978a75f..f5778011077 100644
--- a/reactos/lib/setupapi/devinst.c
+++ b/reactos/lib/setupapi/devinst.c
@@ -34,6 +34,7 @@
 #include "setupapi.h"
 #include "wine/debug.h"
 #include "wine/unicode.h"
+#include "cfgmgr32.h"
 #include "initguid.h"
 #include "winioctl.h"
 #include "rpc.h"
@@ -469,8 +470,24 @@ BOOL WINAPI SetupDiClassNameFromGuidExA(
         PCSTR MachineName,
         PVOID Reserved)
 {
-  FIXME("\n");
-  return FALSE;
+    WCHAR ClassNameW[MAX_CLASS_NAME_LEN];
+    LPWSTR MachineNameW = NULL;
+    BOOL ret;
+
+    if (MachineName)
+        MachineNameW = MultiByteToUnicode(MachineName, CP_ACP);
+    ret = SetupDiClassNameFromGuidExW(ClassGuid, ClassNameW, MAX_CLASS_NAME_LEN,
+     NULL, MachineNameW, Reserved);
+    if (ret)
+    {
+        int len = WideCharToMultiByte(CP_ACP, 0, ClassNameW, -1, ClassName,
+         ClassNameSize, NULL, NULL);
+
+        if (!ClassNameSize && RequiredSize)
+            *RequiredSize = len;
+    }
+    MyFree(MachineNameW);
+    return ret;
 }
 
 /***********************************************************************
@@ -859,8 +876,7 @@ static HDEVINFO SETUP_CreateSerialDeviceList(void)
                 size *= 2;
                 if (devices != buf)
                     HeapFree(GetProcessHeap(), 0, devices);
-                devices = (LPWSTR)HeapAlloc(GetProcessHeap(), 0,
-                 size * sizeof(WCHAR));
+                devices = HeapAlloc(GetProcessHeap(), 0, size * sizeof(WCHAR));
                 if (!devices)
                     failed = TRUE;
                 else
@@ -892,7 +908,7 @@ static HDEVINFO SETUP_CreateSerialDeviceList(void)
             {
                 if (!strncmpW(comW, ptr, sizeof(comW) / sizeof(comW[0]) - 1))
                 {
-                    strncpyW(list->names[list->numPorts].name, ptr,
+                    lstrcpynW(list->names[list->numPorts].name, ptr,
                      sizeof(list->names[list->numPorts].name) /
                      sizeof(list->names[list->numPorts].name[0]));
                     TRACE("Adding %s to list\n",
diff --git a/reactos/lib/setupapi/diskspace.c b/reactos/lib/setupapi/diskspace.c
index 4bff4c66f36..c3b303e8896 100644
--- a/reactos/lib/setupapi/diskspace.c
+++ b/reactos/lib/setupapi/diskspace.c
@@ -58,7 +58,7 @@ HDSKSPC WINAPI SetupCreateDiskSpaceListW(PVOID Reserved1, DWORD Reserved2, UINT
     if (rc == 0)
         return NULL;
 
-    list = (LPDISKSPACELIST)HeapAlloc(GetProcessHeap(),0,sizeof(DISKSPACELIST));
+    list = HeapAlloc(GetProcessHeap(),0,sizeof(DISKSPACELIST));
 
     list->dwDriveCount = 0;
     
diff --git a/reactos/lib/setupapi/setupcab.c b/reactos/lib/setupapi/setupcab.c
index 470f8aaa933..0a00ef996f6 100644
--- a/reactos/lib/setupapi/setupcab.c
+++ b/reactos/lib/setupapi/setupcab.c
@@ -363,9 +363,7 @@ static INT_PTR sc_FNNOTIFY_A(FDINOTIFICATIONTYPE fdint, PFDINOTIFICATION pfdin)
     } else {
       if (mysterio[0]) {
         /* some easy paranoia.  no such carefulness exists on the wide API IIRC */
-        mysterio[SIZEOF_MYSTERIO - 1] = '\0';
-        strncpy(pfdin->psz3, &(mysterio[0]), 255);
-        mysterio[255] = '\0';
+        lstrcpynA(pfdin->psz3, &(mysterio[0]), SIZEOF_MYSTERIO);
       }
       return 0;
     }
diff --git a/reactos/lib/setupapi/stubs.c b/reactos/lib/setupapi/stubs.c
index fa0cbd8a498..f392481a362 100644
--- a/reactos/lib/setupapi/stubs.c
+++ b/reactos/lib/setupapi/stubs.c
@@ -99,7 +99,7 @@ BOOL WINAPI SetupCopyOEMInfA(PCSTR sourceinffile, PCSTR sourcemedialoc,
 			    DWORD destnamesize, PDWORD required,
 			    PSTR *destinfnamecomponent)
 {
-  FIXME("stub: source %s location %s ...\n",sourceinffile, sourcemedialoc);
+  FIXME("stub: source %s location %s ...\n",sourceinffile, sourcemedialoc);
   return FALSE;
 }