diff --git a/firmware/target/arm/usb-s3c6400x.c b/firmware/target/arm/usb-s3c6400x.c
index ba3b69a02e..eb7a0170bf 100644
--- a/firmware/target/arm/usb-s3c6400x.c
+++ b/firmware/target/arm/usb-s3c6400x.c
@@ -258,7 +258,7 @@ void INT_USB_FUNC(void)
                 if (!i)
                 {
                     DOEPTSIZ0 = 0x20080040;
-                    DOEPDMA0 = (uint32_t)&ctrlreq;
+                    DOEPDMA0 = &ctrlreq;
                     DOEPCTL0 |= 0x84000000;
                 }
                 DOEPINT(i) = epints;
@@ -286,12 +286,12 @@ static void ep_send(int ep, const void *ptr, int length)
     if (!length)
     {
         DIEPTSIZ(ep) = 1 << 19;  /* one empty packet */
-        DIEPDMA(ep) = 0x10000000;  /* dummy address */
+        DIEPDMA(ep) = NULL;
     }
     else
     {
         DIEPTSIZ(ep) = length | (packets << 19);
-        DIEPDMA(ep) = (uint32_t)ptr;
+        DIEPDMA(ep) = ptr;
     }
     clean_dcache();
     DIEPCTL(ep) |= 0x84000000;  /* EPx OUT ENABLE CLEARNAK */
@@ -308,12 +308,12 @@ static void ep_recv(int ep, void *ptr, int length)
     if (!length)
     {
         DOEPTSIZ(ep) = 1 << 19;  /* one empty packet */
-        DOEPDMA(ep) = 0x10000000;  /* dummy address */
+        DOEPDMA(ep) = NULL;
     }
     else
     {
         DOEPTSIZ(ep) = length | (packets << 19);
-        DOEPDMA(ep) = (uint32_t)ptr;
+        DOEPDMA(ep) = ptr;
     }
     clean_dcache();
     DOEPCTL(ep) |= 0x84000000;  /* EPx OUT ENABLE CLEARNAK */