diff --git a/tests/backupcompatibility.py b/tests/backupcompatibility.py
index 775db92f..826830d2 100644
--- a/tests/backupcompatibility.py
+++ b/tests/backupcompatibility.py
@@ -167,14 +167,20 @@ class TC_00_BackupCompatibility(qubes.tests.BackupTestsMixin, qubes.tests.QubesT
 
     def create_volatile_img(self, filename):
         self.create_sparse(filename, 11.5*2**30)
-        sfdisk_input="0,1024,S\n,10240,L\n"
-        p = subprocess.Popen(["/usr/sbin/sfdisk", "--no-reread", "-u",
-                                   "M",
-                               filename], stdout=open("/dev/null","w"),
-                              stderr=subprocess.STDOUT, stdin=subprocess.PIPE)
-        p.communicate(input=sfdisk_input)
-        self.assertEqual(p.returncode, 0, "sfdisk failed with code %d" % p
-                         .returncode)
+        # here used to be sfdisk call with "0,1024,S\n,10240,L\n" input,
+        # but since sfdisk folks like to change command arguments in
+        # incompatible way, have an partition table verbatim here
+        ptable = (
+            '\x00\x00\x00\x00\x00\x00\x00\x00\xab\x39\xd5\xd4\x00\x00\x20\x00'
+            '\x00\x21\xaa\x82\x82\x28\x08\x00\x00\x00\x00\x00\x00\x20\xaa\x00'
+            '\x82\x29\x15\x83\x9c\x79\x08\x00\x00\x20\x00\x00\x01\x40\x00\x00'
+            '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
+            '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xaa\x55'
+        )
+        with open(filename, 'r+') as f:
+            f.seek(0x1b0)
+            f.write(ptable)
+
         # TODO: mkswap
 
     def fullpath(self, name):