diff --git a/reactos/dll/shellext/devcpux/devcpux.def b/reactos/dll/shellext/devcpux/devcpux.def
deleted file mode 100644
index caa8fe977f2..00000000000
--- a/reactos/dll/shellext/devcpux/devcpux.def
+++ /dev/null
@@ -1,7 +0,0 @@
-LIBRARY devcpux.dll
-
-EXPORTS
-
-PropSheetExtProc@12
-
-; EOF
diff --git a/reactos/dll/shellext/devcpux/devcpux.rbuild b/reactos/dll/shellext/devcpux/devcpux.rbuild
index fe492d99003..050274324a6 100644
--- a/reactos/dll/shellext/devcpux/devcpux.rbuild
+++ b/reactos/dll/shellext/devcpux/devcpux.rbuild
@@ -1,5 +1,5 @@
 <module name="devcpux" type="win32dll" installbase="system32" installname="devcpux.dll" unicode="yes">
-	<importlibrary definition="devcpux.def" />
+	<importlibrary definition="devcpux.spec" />
 	<include base="devcpux">.</include>
 	<include base="ReactOS">include/reactos/wine</include>
 	<library>kernel32</library>
diff --git a/reactos/dll/shellext/devcpux/devcpux.spec b/reactos/dll/shellext/devcpux/devcpux.spec
new file mode 100644
index 00000000000..50281f192ce
--- /dev/null
+++ b/reactos/dll/shellext/devcpux/devcpux.spec
@@ -0,0 +1 @@
+@ stdcall PropSheetExtProc(ptr ptr ptr)
diff --git a/reactos/dll/shellext/devcpux/processor.c b/reactos/dll/shellext/devcpux/processor.c
index 4e8359d8b18..01636ba3a5a 100644
--- a/reactos/dll/shellext/devcpux/processor.c
+++ b/reactos/dll/shellext/devcpux/processor.c
@@ -14,7 +14,7 @@
 #include "resource.h"
 
 HINSTANCE g_hInstance = NULL;
-int APIENTRY ProcessorDlgProc (HWND hDlg, UINT uMessage, WPARAM wParam, LPARAM lParam);
+LRESULT CALLBACK ProcessorDlgProc (HWND hDlg, UINT uMessage, WPARAM wParam, LPARAM lParam);
 
 BOOL
 APIENTRY
@@ -74,8 +74,8 @@ AddFeature(WCHAR* szFeatures, WCHAR* Feature, BOOL* bFirst)
 	wcscat(szFeatures, Feature);
 }
 
-int
-APIENTRY
+LRESULT
+CALLBACK
 ProcessorDlgProc (HWND hDlg, UINT uMessage, WPARAM wParam, LPARAM lParam)
 {
 	switch (uMessage) {
diff --git a/reactos/dll/shellext/slayer/slayer.def b/reactos/dll/shellext/slayer/slayer.def
deleted file mode 100644
index 6330852ebf9..00000000000
--- a/reactos/dll/shellext/slayer/slayer.def
+++ /dev/null
@@ -1,9 +0,0 @@
-LIBRARY slayer.dll
-
-EXPORTS
-DllCanUnloadNow@0
-DllGetClassObject@12
-DllRegisterServer@0
-DllUnregisterServer@0
-
-; EOF
diff --git a/reactos/dll/shellext/slayer/slayer.rbuild b/reactos/dll/shellext/slayer/slayer.rbuild
index d641b808eaf..bfe216c142e 100644
--- a/reactos/dll/shellext/slayer/slayer.rbuild
+++ b/reactos/dll/shellext/slayer/slayer.rbuild
@@ -1,5 +1,5 @@
 <module name="slayer" type="win32dll" baseaddress="${BASEADDRESS_SLAYER}" installbase="system32" installname="slayer.dll" unicode="yes">
-	<importlibrary definition="slayer.def" />
+	<importlibrary definition="slayer.spec" />
 	<include base="slayer">.</include>
 	<library>kernel32</library>
 	<library>user32</library>
diff --git a/reactos/dll/shellext/slayer/slayer.spec b/reactos/dll/shellext/slayer/slayer.spec
new file mode 100644
index 00000000000..f0c566e949d
--- /dev/null
+++ b/reactos/dll/shellext/slayer/slayer.spec
@@ -0,0 +1,4 @@
+@ stdcall DllCanUnloadNow()
+@ stdcall DllGetClassObject(long long ptr)
+@ stdcall DllRegisterServer()
+@ stdcall DllUnregisterServer()