diff --git a/libs/spandsp/src/spandsp/t30.h b/libs/spandsp/src/spandsp/t30.h
index 88dd94be90..ee842afea8 100644
--- a/libs/spandsp/src/spandsp/t30.h
+++ b/libs/spandsp/src/spandsp/t30.h
@@ -375,9 +375,9 @@ enum
     /*! T.88 monochrome JBIG2 compression */
     T30_SUPPORT_T88_COMPRESSION = 0x400,
     /*! Dither a gray scale image down a simple bilevel image, with rescaling to fit a FAX page */
-    T30_SUPPORT_GRAY_TO_BILEVEL = 0x40000000,
+    T30_SUPPORT_GRAY_TO_BILEVEL = 0x10000000,
     /*! Dither a colour image down a simple bilevel image, with rescaling to fit a FAX page */
-    T30_SUPPORT_COLOUR_TO_BILEVEL = 0x80000000
+    T30_SUPPORT_COLOUR_TO_BILEVEL = 0x20000000
 };
 
 enum