diff --git a/yocto-poky/meta/files/ext-sdk-prepare.py b/yocto-poky/meta/files/ext-sdk-prepare.py
new file mode 100644
index 0000000..605e2eb
--- /dev/null
+++ b/yocto-poky/meta/files/ext-sdk-prepare.py
@@ -0,0 +1,103 @@
+#!/usr/bin/env python
+
+# Prepare the build system within the extensible SDK
+
+import sys
+import os
+import subprocess
+
+def exec_watch(cmd, **options):
+    """Run program with stdout shown on sys.stdout"""
+    if isinstance(cmd, basestring) and not "shell" in options:
+        options["shell"] = True
+
+    process = subprocess.Popen(
+        cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, **options
+    )
+
+    buf = ''
+    while True:
+        out = process.stdout.read(1)
+        if out:
+            sys.stdout.write(out)
+            sys.stdout.flush()
+            buf += out
+        elif out == '' and process.poll() != None:
+            break
+
+    return process.returncode, buf
+
+def check_unexpected(lines, recipes):
+    """Check for unexpected output lines from dry run"""
+    unexpected = []
+    for line in lines.splitlines():
+        if 'Running task' in line:
+            for recipe in recipes:
+                if recipe in line:
+                    break
+            else:
+                line = line.split('Running', 1)[-1]
+                if 'do_rm_work' not in line:
+                    unexpected.append(line.rstrip())
+        elif 'Running setscene' in line:
+            unexpected.append(line.rstrip())
+    return unexpected
+
+def main():
+    if len(sys.argv) < 2:
+        sdk_targets = []
+    else:
+        sdk_targets = ' '.join(sys.argv[1:]).split()
+    if not sdk_targets:
+        # Just do a parse so the cache is primed
+        ret, _ = exec_watch('bitbake -p')
+        return ret
+
+    print('Preparing SDK for %s...' % ', '.join(sdk_targets))
+
+    ret, out = exec_watch('bitbake %s --setscene-only' % ' '.join(sdk_targets))
+    if ret:
+        return ret
+
+    targetlist = []
+    for target in sdk_targets:
+        if ':' in target:
+            target = target.split(':')[0]
+        if not target in targetlist:
+            targetlist.append(target)
+
+    recipes = []
+    for target in targetlist:
+        try:
+            out = subprocess.check_output(('bitbake -e %s' % target).split(), stderr=subprocess.STDOUT)
+            for line in out.splitlines():
+                if line.startswith('FILE='):
+                    splitval = line.rstrip().split('=')
+                    if len(splitval) > 1:
+                        recipes.append(splitval[1].strip('"'))
+                    break
+        except subprocess.CalledProcessError as e:
+            print('ERROR: Failed to get recipe for target %s:\n%s' % (target, e.output))
+            return 1
+
+    try:
+        out = subprocess.check_output('bitbake %s -n' % ' '.join(sdk_targets), stderr=subprocess.STDOUT, shell=True)
+        unexpected = check_unexpected(out, recipes)
+    except subprocess.CalledProcessError as e:
+        print('ERROR: Failed to execute dry-run:\n%s' % e.output)
+        return 1
+
+    if unexpected:
+        print('ERROR: Unexpected tasks or setscene left over to be executed:')
+        for line in unexpected:
+            print('  ' + line)
+        return 1
+
+if __name__ == "__main__":
+    try:
+        ret = main()
+    except Exception:
+        ret = 1
+        import traceback
+        traceback.print_exc()
+    sys.exit(ret)