diff --git a/Tools/ardupilotwaf/boards.py b/Tools/ardupilotwaf/boards.py
index 7d34ae42ea..0ac7760350 100644
--- a/Tools/ardupilotwaf/boards.py
+++ b/Tools/ardupilotwaf/boards.py
@@ -841,6 +841,7 @@ class esp32(Board):
         env.CFLAGS += [
             '-fno-inline-functions',
             '-mlongcalls',
+            '-fsingle-precision-constant',
         ]
         env.CFLAGS.remove('-Werror=undef')
 
@@ -856,6 +857,8 @@ class esp32(Board):
                          '-Wno-sign-compare',
                          '-fno-inline-functions',
                          '-mlongcalls',
+                         '-fsingle-precision-constant', # force const vals to be float , not double. so 100.0 means 100.0f 
+                         '-fno-threadsafe-statics',
                          '-DCYGWIN_BUILD']
         env.CXXFLAGS.remove('-Werror=undef')
         env.CXXFLAGS.remove('-Werror=shadow')