diff --git a/doc/compatibility/fpga.rst b/doc/compatibility/fpga.rst
index f6a42bd..353c6d0 100644
--- a/doc/compatibility/fpga.rst
+++ b/doc/compatibility/fpga.rst
@@ -6,6 +6,7 @@ FPGAs
 .. include:: fpga.inc
 
 * AS: Active Serial flash mode
+* EF: External Flash
 * IF: Internal Flash
 * NA: Not Available
 * NT: Not Tested