diff --git a/docs/fdroid.texi b/docs/fdroid.texi
index 3cc1f5f7..09c57380 100644
--- a/docs/fdroid.texi
+++ b/docs/fdroid.texi
@@ -772,6 +772,11 @@ insert literal commas, or as the last character on a line to join that
 line with the next. It has no special meaning in other contexts; in
 particular, literal backslashes should not be escaped.
 
+Note that nothing should be build during this prebuild phase - scanning
+of the code and building of the source tarball, for example, take place
+after this. For custom actions that actually build things, use 'build'
+instead.
+
 You can use $$name$$ to substitute the path to a referenced srclib - see
 the @code{srclib} directory for details of this.
 
@@ -785,6 +790,15 @@ takes place.
 You can use $$SDK$$, $$NDK$$ and $$MVN3$$ to substitute the paths to the
 android SDK and NDK directories, and maven 3 executable respectively.
 
+@item build=xxxx
+As for 'prebuild', but runs during the actual build phase (but before the
+main ant/maven build). Use this only for actions that do actual building.
+Any prepartion of the source code should be done using 'init' or 'prebuild'.
+
+You can use $$SDK$$, $$NDK$$ and $$MVN3$$ to substitute the paths to the
+android SDK and NDK directories, and maven 3 executable respectively.
+
+
 @item novcheck=yes 
 Don't check that the version name and code in the resulting apk are
 correct by looking at the build output - assume the metadata is
diff --git a/fdroidserver/build.py b/fdroidserver/build.py
index c2e2fb84..40d1e987 100644
--- a/fdroidserver/build.py
+++ b/fdroidserver/build.py
@@ -265,7 +265,7 @@ def build_local(app, thisbuild, vcs, build_dir, output_dir, extlib_dir, tmp_dir,
     """Do a build locally."""
 
     # Prepare the source code...
-    root_dir = common.prepare_source(vcs, app, thisbuild,
+    root_dir, srclibpaths = common.prepare_source(vcs, app, thisbuild,
             build_dir, extlib_dir, sdk_path, ndk_path,
             javacc_path, mvn3, verbose)
 
@@ -291,6 +291,22 @@ def build_local(app, thisbuild, vcs, build_dir, output_dir, extlib_dir, tmp_dir,
     tarball.add(build_dir, tarname, exclude=tarexc)
     tarball.close()
 
+    # Run a build command if one is required...
+    if 'build' in thisbuild:
+        prebuild = build['build']
+        # Substitute source library paths into prebuild commands...
+        for name, libpath in srclibpaths:
+            libpath = os.path.relpath(libpath, root_dir)
+            prebuild = prebuild.replace('$$' + name + '$$', libpath)
+        prebuild = prebuild.replace('$$SDK$$', sdk_path)
+        prebuild = prebuild.replace('$$NDK$$', ndk_path)
+        prebuild = prebuild.replace('$$MVN3$$', mvn3)
+        p = subprocess.Popen(prebuild, cwd=root_dir, shell=True,
+                stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        out, err = p.communicate()
+        if p.returncode != 0:
+            raise BuildException("Error running build command", out, err)
+
     # Build native stuff if required...
     if thisbuild.get('buildjni') not in (None, 'no'):
         jni_components = thisbuild.get('buildjni')
diff --git a/fdroidserver/common.py b/fdroidserver/common.py
index a948f821..050a0fa8 100644
--- a/fdroidserver/common.py
+++ b/fdroidserver/common.py
@@ -1642,8 +1642,10 @@ def getsrclib(spec, extlib_dir, sdk_path, basepath=False):
 #  'javacc_path' - the path to javacc
 #  'mvn3'        - the path to the maven 3 executable
 #  'verbose'     - optional: verbose or not (default=False)
-# Returns the root directory, which may be the same as 'build_dir' or may
-# be a subdirectory of it.
+# Returns the (root, srclibpaths) where:
+#   'root' is the root directory, which may be the same as 'build_dir' or may
+#          be a subdirectory of it.
+#   'srclibpaths' is information on the srclibs being used
 def prepare_source(vcs, app, build, build_dir, extlib_dir, sdk_path, ndk_path, javacc_path, mvn3, verbose=False):
 
     # Optionally, the actual app source can be in a subdirectory...
@@ -1970,7 +1972,7 @@ def prepare_source(vcs, app, build, build_dir, extlib_dir, sdk_path, ndk_path, j
             'build.properties'], cwd=root_dir) !=0:
             raise BuildException("Failed to amend build.properties")
 
-    return root_dir
+    return (root_dir, srclibpaths)
 
 
 # Scan the source code in the given directory (and all subdirectories)
diff --git a/fdroidserver/scanner.py b/fdroidserver/scanner.py
index 2d307a32..9af74da9 100644
--- a/fdroidserver/scanner.py
+++ b/fdroidserver/scanner.py
@@ -98,7 +98,7 @@ def main():
                         print "..scanning version " + thisbuild['version']
 
                         # Prepare the source code...
-                        root_dir = common.prepare_source(vcs, app, thisbuild,
+                        root_dir, _ = common.prepare_source(vcs, app, thisbuild,
                                 build_dir, extlib_dir, sdk_path, ndk_path, javacc_path, mvn3, options.verbose)
 
                         # Do the scan...