diff --git a/b2g/installer/Makefile.in b/b2g/installer/Makefile.in
index 754312a9aa9..d139117bdaf 100644
--- a/b2g/installer/Makefile.in
+++ b/b2g/installer/Makefile.in
@@ -97,6 +97,8 @@ GARBAGE += $(MOZ_PKG_MANIFEST)
 endif
 
 ifdef FXOS_SIMULATOR
+export MAKE
+
 .PHONY: simulator
 simulator: make-package
 	@echo 'Building simulator addon...'
diff --git a/build/pymake/make.py b/build/pymake/make.py
index 6334b464c46..0857f3f8ccf 100755
--- a/build/pymake/make.py
+++ b/build/pymake/make.py
@@ -18,13 +18,12 @@ if __name__ == '__main__':
     import subprocess
     mozmake = os.path.join(os.path.dirname(__file__), '..', '..',
         'mozmake.exe')
-    if os.path.exists(mozmake):
-        cmd = [mozmake]
-        cmd.extend(sys.argv[1:])
-        shell = os.environ.get('SHELL')
-        if shell and not shell.lower().endswith('.exe'):
-            cmd += ['SHELL=%s.exe' % shell]
-        sys.exit(subprocess.call(cmd))
+    cmd = [mozmake]
+    cmd.extend(sys.argv[1:])
+    shell = os.environ.get('SHELL')
+    if shell and not shell.lower().endswith('.exe'):
+        cmd += ['SHELL=%s.exe' % shell]
+    sys.exit(subprocess.call(cmd))
 
   sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)
   sys.stderr = os.fdopen(sys.stderr.fileno(), 'w', 0)
diff --git a/config/baseconfig.mk b/config/baseconfig.mk
index b4723a97068..1d4ee2d970c 100644
--- a/config/baseconfig.mk
+++ b/config/baseconfig.mk
@@ -25,9 +25,12 @@ _OBJ_SUFFIX := $(OBJ_SUFFIX)
 OBJ_SUFFIX = $(error config/config.mk needs to be included before using OBJ_SUFFIX)
 
 ifeq ($(HOST_OS_ARCH),WINNT)
-# We only support building with pymake or a non-msys gnu make version
+# We only support building with a non-msys gnu make version
 # strictly above 4.0.
-ifndef .PYMAKE
+ifdef .PYMAKE
+$(error Pymake is no longer supported. Please upgrade to MozillaBuild 1.9 or newer and build with 'mach' or 'mozmake')
+endif
+
 ifeq (a,$(firstword a$(subst /, ,$(abspath .))))
 $(error MSYS make is not supported)
 endif
@@ -37,7 +40,7 @@ endif
 ifneq (4.0-,$(firstword $(sort 4.0- $(MAKE_VERSION))))
 $(error Make version too old. Only versions strictly greater than 4.0 are supported.)
 endif
-endif
+
 ifdef INCLUDED_AUTOCONF_MK
 ifeq (a,$(firstword a$(subst /, ,$(srcdir))))
 $(error MSYS-style srcdir are not supported for Windows builds.)
@@ -45,11 +48,7 @@ endif
 endif
 endif # WINNT
 
-ifdef .PYMAKE
-include_deps = $(eval $(if $(2),,-)includedeps $(1))
-else
 include_deps = $(eval $(if $(2),,-)include $(1))
-endif
 
 ifndef INCLUDED_AUTOCONF_MK
 default::
diff --git a/python/mozbuild/mozbuild/base.py b/python/mozbuild/mozbuild/base.py
index 6afb09fbe9a..3456617a679 100644
--- a/python/mozbuild/mozbuild/base.py
+++ b/python/mozbuild/mozbuild/base.py
@@ -396,7 +396,7 @@ class MozbuildObject(ProcessExecutionMixin):
             srcdir=False, allow_parallel=True, line_handler=None,
             append_env=None, explicit_env=None, ignore_errors=False,
             ensure_exit_code=0, silent=True, print_directory=True,
-            pass_thru=False, num_jobs=0, force_pymake=False):
+            pass_thru=False, num_jobs=0):
         """Invoke make.
 
         directory -- Relative directory to look for Makefile in.
@@ -408,11 +408,10 @@ class MozbuildObject(ProcessExecutionMixin):
         silent -- If True (the default), run make in silent mode.
         print_directory -- If True (the default), have make print directories
         while doing traversal.
-        force_pymake -- If True, pymake will be used instead of GNU make.
         """
         self._ensure_objdir_exists()
 
-        args = self._make_path(force_pymake=force_pymake)
+        args = self._make_path()
 
         if directory:
             args.extend(['-C', directory.replace(os.sep, '/')])
@@ -475,44 +474,45 @@ class MozbuildObject(ProcessExecutionMixin):
 
         return fn(**params)
 
-    def _make_path(self, force_pymake=False):
-        if self._is_windows() and not force_pymake:
-            # Use gnumake if it's available and we can verify it's a working
-            # version.
-            baseconfig = os.path.join(self.topsrcdir, 'config', 'baseconfig.mk')
-            if os.path.exists(baseconfig):
+    def _make_path(self):
+        baseconfig = os.path.join(self.topsrcdir, 'config', 'baseconfig.mk')
+
+        def validate_make(make):
+            if os.path.exists(baseconfig) and os.path.exists(make):
+                cmd = [make, '-f', baseconfig]
+                if self._is_windows():
+                    cmd.append('HOST_OS_ARCH=WINNT')
                 try:
-                    make = which.which('gnumake')
-                    subprocess.check_call([make, '-f', baseconfig, 'HOST_OS_ARCH=WINNT'],
-                        stdout=open(os.devnull, 'wb'), stderr=subprocess.STDOUT)
-                    return [make]
+                    subprocess.check_call(cmd, stdout=open(os.devnull, 'wb'),
+                        stderr=subprocess.STDOUT)
                 except subprocess.CalledProcessError:
-                    pass
-                except which.WhichError:
-                    pass
+                    return False
+                return True
+            return False
 
-            # Use mozmake if it's available.
+        possible_makes = ['gmake', 'make', 'mozmake', 'gnumake']
+
+        if 'MAKE' in os.environ:
+            make = os.environ['MAKE']
+            if os.path.isabs(make):
+                if validate_make(make):
+                    return [make]
+            else:
+                possible_makes.insert(0, make)
+
+        for test in possible_makes:
             try:
-                return [which.which('mozmake')]
-            except which.WhichError:
-                pass
-
-        if self._is_windows() or force_pymake:
-            make_py = os.path.join(self.topsrcdir, 'build', 'pymake',
-                'make.py').replace(os.sep, '/')
-
-            # We might want to consider invoking with the virtualenv's Python
-            # some day. But, there is a chicken-and-egg problem w.r.t. when the
-            # virtualenv is created.
-            return [sys.executable, make_py]
-
-        for test in ['gmake', 'make']:
-            try:
-                return [which.which(test)]
+                make = which.which(test)
             except which.WhichError:
                 continue
+            if validate_make(make):
+                return [make]
 
-        raise Exception('Could not find a suitable make implementation.')
+        if self._is_windows():
+            raise Exception('Could not find a suitable make implementation.\n'
+                'Please use MozillaBuild 1.9 or newer')
+        else:
+            raise Exception('Could not find a suitable make implementation.')
 
     def _run_command_in_srcdir(self, **args):
         return self.run_process(cwd=self.topsrcdir, **args)
diff --git a/python/mozbuild/mozbuild/mach_commands.py b/python/mozbuild/mozbuild/mach_commands.py
index e0a839b31e9..6dc01b1d3ee 100644
--- a/python/mozbuild/mozbuild/mach_commands.py
+++ b/python/mozbuild/mozbuild/mach_commands.py
@@ -267,15 +267,13 @@ class Build(MachCommandBase):
     @CommandArgument('--jobs', '-j', default='0', metavar='jobs', type=int,
         help='Number of concurrent jobs to run. Default is the number of CPUs.')
     @CommandArgument('what', default=None, nargs='*', help=BUILD_WHAT_HELP)
-    @CommandArgument('-p', '--pymake', action='store_true',
-        help='Force using pymake over GNU make.')
     @CommandArgument('-X', '--disable-extra-make-dependencies',
                      default=False, action='store_true',
                      help='Do not add extra make dependencies.')
     @CommandArgument('-v', '--verbose', action='store_true',
         help='Verbose output for what commands the build is running.')
-    def build(self, what=None, pymake=False,
-        disable_extra_make_dependencies=None, jobs=0, verbose=False):
+    def build(self, what=None, disable_extra_make_dependencies=None, jobs=0,
+        verbose=False):
         import which
         from mozbuild.controller.building import BuildMonitor
         from mozbuild.util import resolve_target_to_make
@@ -343,8 +341,8 @@ class Build(MachCommandBase):
                 # comprehensive history lesson.
                 self._run_make(directory=self.topobjdir,
                     target='backend.RecursiveMakeBackend',
-                    force_pymake=pymake, line_handler=output.on_line,
-                    log=False, print_directory=False)
+                    line_handler=output.on_line, log=False,
+                    print_directory=False)
 
                 # Build target pairs.
                 for make_dir, make_target in target_pairs:
@@ -355,8 +353,7 @@ class Build(MachCommandBase):
                     status = self._run_make(directory=make_dir, target=make_target,
                         line_handler=output.on_line, log=False, print_directory=False,
                         ensure_exit_code=False, num_jobs=jobs, silent=not verbose,
-                        append_env={b'NO_BUILDSTATUS_MESSAGES': b'1'},
-                        force_pymake=pymake)
+                        append_env={b'NO_BUILDSTATUS_MESSAGES': b'1'})
 
                     if status != 0:
                         break
@@ -365,7 +362,7 @@ class Build(MachCommandBase):
                 status = self._run_make(srcdir=True, filename='client.mk',
                     line_handler=output.on_line, log=False, print_directory=False,
                     allow_parallel=False, ensure_exit_code=False, num_jobs=jobs,
-                    silent=not verbose, force_pymake=pymake)
+                    silent=not verbose)
 
                 make_extra = self.mozconfig['make_extra'] or []
                 make_extra = dict(m.split('=', 1) for m in make_extra)
@@ -374,8 +371,7 @@ class Build(MachCommandBase):
                 if moz_automation and status == 0:
                     status = self._run_make(target='automation/build',
                         line_handler=output.on_line, log=False, print_directory=False,
-                        ensure_exit_code=False, num_jobs=jobs, silent=not verbose,
-                        force_pymake=pymake)
+                        ensure_exit_code=False, num_jobs=jobs, silent=not verbose)
 
                 self.log(logging.WARNING, 'warning_summary',
                     {'count': len(monitor.warnings_database)},