diff --git a/Tools/CPUInfo/EKF_Maths.h b/Tools/CPUInfo/EKF_Maths.h
index 017fae43a3..6254203ac4 100644
--- a/Tools/CPUInfo/EKF_Maths.h
+++ b/Tools/CPUInfo/EKF_Maths.h
@@ -4,10 +4,9 @@
   data structure for measuring speed of EKF mag fusion code
  */
 #include <AP_Math/AP_Math.h>
+#include <AP_Math/ftype.h>
 #include <stdint.h>
 
-typedef float ftype;
-
 class EKF_Maths {
 public:
     EKF_Maths() {}
diff --git a/Tools/ardupilotwaf/boards.py b/Tools/ardupilotwaf/boards.py
index c9ba9a534a..d252d188f2 100644
--- a/Tools/ardupilotwaf/boards.py
+++ b/Tools/ardupilotwaf/boards.py
@@ -342,10 +342,10 @@ class Board:
                     env.ROMFS_FILES += [(f,'libraries/AP_OSD/fonts/'+f)]
 
         if cfg.options.ekf_double:
-            env.CXXFLAGS += ['-DHAL_EKF_DOUBLE=1']
+            env.CXXFLAGS += ['-DHAL_WITH_EKF_DOUBLE=1']
 
         if cfg.options.ekf_single:
-            env.CXXFLAGS += ['-DHAL_EKF_DOUBLE=0']
+            env.CXXFLAGS += ['-DHAL_WITH_EKF_DOUBLE=0']
 
     def pre_build(self, bld):
         '''pre-build hook that gets called before dynamic sources'''
diff --git a/Tools/autotest/sim_vehicle.py b/Tools/autotest/sim_vehicle.py
index 86e908991b..d023e84cc5 100755
--- a/Tools/autotest/sim_vehicle.py
+++ b/Tools/autotest/sim_vehicle.py
@@ -327,6 +327,12 @@ def do_build(opts, frame_options):
     if opts.postype_single:
         cmd_configure.append("--postype-single")
 
+    if opts.ekf_double:
+        cmd_configure.append("--ekf-double")
+
+    if opts.ekf_single:
+        cmd_configure.append("--ekf-single")
+
     pieces = [shlex.split(x) for x in opts.waf_configure_args]
     for piece in pieces:
         cmd_configure.extend(piece)
@@ -1088,6 +1094,12 @@ group_sim.add_option("", "--sysid",
 group_sim.add_option("--postype-single",
                      action='store_true',
                      help="force single precision postype_t")
+group_sim.add_option("--ekf-double",
+                     action='store_true',
+                     help="use double precision in EKF")
+group_sim.add_option("--ekf-single",
+                     action='store_true',
+                     help="use single precision in EKF")
 parser.add_option_group(group_sim)