--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -883,41 +883,13 @@
             return s
         }
 
-        let beta = output(
-            Command::new("git")
-                .arg("ls-remote")
-                .arg("origin")
-                .arg("beta")
-                .current_dir(&self.src)
-        );
-        let beta = beta.trim().split_whitespace().next().unwrap();
-        let master = output(
-            Command::new("git")
-                .arg("ls-remote")
-                .arg("origin")
-                .arg("master")
-                .current_dir(&self.src)
-        );
-        let master = master.trim().split_whitespace().next().unwrap();
-
-        // Figure out where the current beta branch started.
-        let base = output(
-            Command::new("git")
-                .arg("merge-base")
-                .arg(beta)
-                .arg(master)
-                .current_dir(&self.src),
-        );
-        let base = base.trim();
-
-        // Next figure out how many merge commits happened since we branched off
-        // beta. That's our beta number!
+        // Debian: read beta number from "version" file, this is only available
+        // in the rustc upstream tarballs and not their git
         let count = output(
-            Command::new("git")
-                .arg("rev-list")
-                .arg("--count")
-                .arg("--merges")
-                .arg(format!("{}...HEAD", base))
+            Command::new("sed")
+                .arg("-re")
+                .arg(r"s/[0-9]+.[0-9]+.[0-9]+-beta.([0-9]+) \(.*\)/\1/g")
+                .arg("version")
                 .current_dir(&self.src),
         );
         let n = count.trim().parse().unwrap();