diff --git a/install/variables/disk.py b/install/variables/disk.py
index 827081b..b0f99c1 100644
--- a/install/variables/disk.py
+++ b/install/variables/disk.py
@@ -109,7 +109,7 @@ class VariableOsDeviceDev(ReadonlyVariable,DeviceHelper):
         pass
     def get(self):
         """Get device /dev name"""
-        if self.master is None:
+        if self.master is None and not self.Get('cl_ebuild_phase'):
             try:
                 self.master, slave = pty.openpty()
             except OSError: