diff --git a/modules/steps.py b/modules/steps.py
index a6ec341..300ae72 100644
--- a/modules/steps.py
+++ b/modules/steps.py
@@ -22,10 +22,12 @@
 import os
 import shutil
 import re
+import multiprocessing
 
 from logging import debug as D
 from logging import info as I
 from logging import warning as W
+from logging import error as E
 
 from errors import Error, DevtoolError, CompilationError
 from buildhistory import BuildHistory
@@ -104,31 +106,87 @@ def devtool_upgrade(devtool, bb, git, opts, group):
     for p in group['pkgs']:
         _devtool_upgrade(devtool, bb, git, opts, p)
 
-def _compile(bb, pkg, machine, workdir):
-        try:
-            bb.complete(pkg, machine)
-        except Error as e:
-            with open("{}/bitbake-output-{}.txt".format(workdir, machine), 'w') as f:
-                f.write(e.stdout + e.stderr)
-            for line in e.stdout.split("\n") + e.stderr.split("\n"):
-                # version going backwards is not a real error
-                if re.match(".* went backwards which would break package feeds .*", line):
-                    break
-                # 'not in COMPATIBLE_HOST/MACHINE is not a real error
-                if re.match(".*not in COMPATIBLE.*", line):
-                    break
-            else:
-                raise CompilationError()
+def _compile_worker(args):
+    """Worker function for multiprocess compilation. Runs in a separate process."""
+    pkg, machine, workdir, orig_builddir, use_orig = args
+    from utils.bitbake import Bitbake
+
+    if use_orig:
+        builddir = orig_builddir
+    else:
+        builddir = "{}-{}".format(orig_builddir, machine)
+        os.makedirs(builddir, exist_ok=True)
+
+        new_conf = os.path.join(builddir, "conf")
+        if os.path.isdir(new_conf):
+            shutil.rmtree(new_conf)
+        shutil.copytree(os.path.join(orig_builddir, "conf"), new_conf)
+
+    os.environ["BUILDDIR"] = builddir
+    os.environ["BBPATH"] = builddir
+
+    bb = Bitbake(builddir)
+    try:
+        bb.complete(pkg, machine)
+        return (machine, True, None)
+    except Error as e:
+        with open("{}/bitbake-output-{}.txt".format(workdir, machine), 'w') as f:
+            f.write(e.stdout + e.stderr)
+        for line in e.stdout.split("\n") + e.stderr.split("\n"):
+            if re.match(".* went backwards which would break package feeds .*", line):
+                return (machine, True, None)
+            if re.match(".*not in COMPATIBLE.*", line):
+                return (machine, True, None)
+        return (machine, False, e.stdout + e.stderr)
+
+def _compile_serial(bb, pkg, machine, workdir):
+    """Compile a single machine serially (original behaviour)."""
+    try:
+        bb.complete(pkg, machine)
+    except Error as e:
+        with open("{}/bitbake-output-{}.txt".format(workdir, machine), 'w') as f:
+            f.write(e.stdout + e.stderr)
+        for line in e.stdout.split("\n") + e.stderr.split("\n"):
+            if re.match(".* went backwards which would break package feeds .*", line):
+                break
+            if re.match(".*not in COMPATIBLE.*", line):
+                break
+        else:
+            raise CompilationError()
 
 def compile(devtool, bb, git, opts, group):
     if opts['skip_compilation']:
         W(" %s: Compilation was skipped by user choice!" % group['name'])
         return
 
-    for machine in opts['machines']:
-        I(" %s: compiling upgraded version for %s ..." % (group['name'], machine))
-        _compile(bb, " ".join([pkg_ctx['PN'] for pkg_ctx in group['pkgs']]), machine, group['workdir'])
-        if opts['buildhistory'] and machine == opts['machines'][0]:
+    pkg = " ".join([pkg_ctx['PN'] for pkg_ctx in group['pkgs']])
+    machines = opts['machines']
+
+    if opts.get('serial_build'):
+        for machine in machines:
+            I(" %s: compiling upgraded version for %s ..." % (group['name'], machine))
+            _compile_serial(bb, pkg, machine, group['workdir'])
+            if opts['buildhistory'] and machine == machines[0]:
+                I(" %s: Checking buildhistory ..." % group['name'])
+                group['buildhistory'].diff()
+    else:
+        orig_builddir = os.environ.get("BUILDDIR", "")
+        worker_args = [(pkg, m, group['workdir'], orig_builddir, i == 0) for i, m in enumerate(machines)]
+
+        I(" %s: compiling upgraded version for %s in parallel ..." % (group['name'], machines))
+        with multiprocessing.Pool(processes=len(machines)) as pool:
+            results = pool.map(_compile_worker, worker_args)
+
+        os.environ["BUILDDIR"] = orig_builddir
+        os.environ["BBPATH"] = orig_builddir
+
+        failed = [(m, err) for m, ok, err in results if not ok]
+        if failed:
+            for m, err in failed:
+                E(" %s: compilation failed for %s" % (group['name'], m))
+            raise CompilationError()
+
+        if opts['buildhistory'] and machines:
             I(" %s: Checking buildhistory ..." % group['name'])
             group['buildhistory'].diff()
 
diff --git a/upgrade-helper.py b/upgrade-helper.py
index 2ceb722..1c05333 100755
--- a/upgrade-helper.py
+++ b/upgrade-helper.py
@@ -108,6 +108,8 @@ def parse_cmdline():
                         help="layers to include in the upgrade research")
     parser.add_argument("--layer-dir", action="store", default='',
                         help="the layers root directory")
+    parser.add_argument("--serial-build", action="store_true", default=False,
+                        help="compile for each machine serially instead of in parallel")
     return parser.parse_args()
 
 def parse_config_file(config_file):
@@ -193,6 +195,7 @@ class Updater(object):
         self.opts['author'] = "Upgrade Helper <%s>" % \
                 settings.get('from', 'uh@not.set')
         self.opts['skip_compilation'] = self.args.skip_compilation
+        self.opts['serial_build'] = self.args.serial_build
         self.opts['buildhistory'] = self._buildhistory_is_enabled()
         self.opts['testimage'] = self._testimage_is_enabled()