diff --git a/10.01_base/2_src/shared/mailbox.h b/10.01_base/2_src/shared/mailbox.h
index 54511ac..f19e7df 100644
--- a/10.01_base/2_src/shared/mailbox.h
+++ b/10.01_base/2_src/shared/mailbox.h
@@ -79,7 +79,7 @@
 #define CPU_PRIORITY_LEVEL_FETCHING	0xff
 
 // data for a requested DMA operation
-#define	PRU_MAX_DMA_WORDCOUNT	512
+#define	PRU_MAX_DMA_WORDCOUNT	(8*512)
 
 #include "ddrmem.h"