diff --git a/Source/Core/Common/make_svnrev.h.vbs b/Source/Core/Common/make_svnrev.h.vbs
index c16e4c8219..76d04a7f84 100644
--- a/Source/Core/Common/make_svnrev.h.vbs
+++ b/Source/Core/Common/make_svnrev.h.vbs
@@ -2,21 +2,38 @@ set wshShell	= CreateObject("WScript.Shell")
 basedir			= wscript.arguments(0)
 outfile			= basedir & "/Src/svnrev.h"
 svncmd			= "SubWCRev ../../.. " & basedir & "/Src/svnrev_template.h " & outfile
+svntestcmd		= "SubWCRev ../../.."
 hgcmd			= "hg svn info"
+const svn		= 0
+const hg		= 1
 
-ret = wshShell.run(svncmd, 0, true)
-if ret <> 0 then ' Perhaps we should just check for 6? dunno/care...
-	set hgexec = wshShell.exec(hgcmd)
+set oFS			= CreateObject("Scripting.fileSystemObject")
+if not oFS.FileExists(outfile) then
+	oFS.CreateTextFile(outfile)
+	file_rev	= 0
+else
+	set oFile	= oFS.OpenTextFile(outfile)
+	set re		= new regexp
+	re.pattern	= "[0-9]+"
+	file_rev	= re.execute(oFile.readline)(0)
+end if
+
+set testexec	= wshShell.exec(svntestcmd)
+do while testexec.status = 0 : wscript.sleep 100 : loop
+if testexec.exitcode = 0 then
+	testout		= testexec.stdout.readall
+	set re		= new regexp
+	re.pattern	= "Updated to revision [0-9]+"
+	cur_rev		= split(re.execute(testout)(0))(3)
+	cur_cms		= svn
+else
+	set hgexec	= wshShell.exec(hgcmd)
 	do while hgexec.status = 0 : wscript.sleep 100 : loop
 	do while true
 		line = hgexec.stdout.readline
 		if instr(line, "Revision") then
-			sline = split(line)
-			wscript.echo "Hg: Working copy at SVN revision " & sline(1)
-			set oFS		= CreateObject("Scripting.fileSystemObject")
-			set oFile	= oFS.CreateTextFile(outfile, true)
-			oFile.writeline("#define SVN_REV_STR """ & sline(1) & """")
-			set oFS 	= nothing
+			cur_rev = split(line)(1)
+			cur_cms	= hg
 			exit do
 		end if
 		if hgexec.stdout.atEndofStream then
@@ -25,3 +42,15 @@ if ret <> 0 then ' Perhaps we should just check for 6? dunno/care...
 		end if
 	loop
 end if
+
+if file_rev = cur_rev then
+	wscript.echo "svnrev.h doesn't need updating"
+	wscript.quit 0
+elseif cur_cms = svn then
+	ret = wshShell.run(svncmd, 0, true)
+elseif cur_cms = hg then
+	set oFile = CreateObject("Scripting.fileSystemObject").CreateTextFile(outfile, true)
+	oFile.writeline("#define SVN_REV_STR """ & cur_rev & """")
+else
+	wscript.echo "WTF, shouldn't be here!"
+end if
\ No newline at end of file