diff --git a/fusee/fusee-primary/src/utils.h b/fusee/fusee-primary/src/utils.h
index 246c3ac..9249897 100644
--- a/fusee/fusee-primary/src/utils.h
+++ b/fusee/fusee-primary/src/utils.h
@@ -80,7 +80,7 @@
     return
         !__builtin_add_overflow_p(addr, size, (uintptr_t)0) && /* the range doesn't overflow */
         check_32bit_address_loadable(addr) && check_32bit_address_loadable(addr + size) && /* bounds are valid */
-        !(addr >= 0x40010000u && addr + size >= 0x40040000u) /* the range doesn't cross MMIO */
+        !(addr >= 0x40010000u && addr < 0x40040000u && addr + size >= 0x40040000u) /* the range doesn't cross MMIO */
     ;
 }
 
diff --git a/fusee/fusee-secondary/src/utils.h b/fusee/fusee-secondary/src/utils.h
index 413a4bd..7dbeaad 100644
--- a/fusee/fusee-secondary/src/utils.h
+++ b/fusee/fusee-secondary/src/utils.h
@@ -80,7 +80,7 @@
     return
         !__builtin_add_overflow_p(addr, size, (uintptr_t)0) && /* the range doesn't overflow */
         check_32bit_address_loadable(addr) && check_32bit_address_loadable(addr + size) && /* bounds are valid */
-        !(addr >= 0x40010000u && addr + size >= 0x40040000u) /* the range doesn't cross MMIO */
+        !(addr >= 0x40010000u && addr < 0x40040000u && addr + size >= 0x40040000u) /* the range doesn't cross MMIO */
     ;
 }