diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index a3217dd..05c2a4a 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -287,7 +287,10 @@
   assert p1.returncode == 0, "mkbootfs of %s ramdisk failed" % (targetname,)
   assert p2.returncode == 0, "minigzip of %s ramdisk failed" % (targetname,)
 
-  cmd = ["mkbootimg", "--kernel", os.path.join(sourcedir, "kernel")]
+  # use MKBOOTIMG from environ, or "mkbootimg" if empty or not set
+  mkbootimg = os.getenv('MKBOOTIMG') or "mkbootimg"
+
+  cmd = [mkbootimg, "--kernel", os.path.join(sourcedir, "kernel")]
 
   fn = os.path.join(sourcedir, "cmdline")
   if os.access(fn, os.F_OK):