diff --git a/sys/src/games/gb/dat.h b/sys/src/games/gb/dat.h
index 110e955de..787c8f839 100644
--- a/sys/src/games/gb/dat.h
+++ b/sys/src/games/gb/dat.h
@@ -69,10 +69,10 @@ enum {
 	WX = 0x4B,
 	KEY1 = 0x4D,
 	VBK = 0x4F,
-	HDMASL = 0x51,
-	HDMASH = 0x52,
-	HDMADL = 0x53,
-	HDMADH = 0x54,
+	HDMASH = 0x51,
+	HDMASL = 0x52,
+	HDMADH = 0x53,
+	HDMADL = 0x54,
 	HDMAC = 0x55,
 	
 	BCPS = 0x68,
diff --git a/sys/src/games/gb/mem.c b/sys/src/games/gb/mem.c
index c5b4bd554..7f2894571 100644
--- a/sys/src/games/gb/mem.c
+++ b/sys/src/games/gb/mem.c
@@ -549,7 +549,7 @@ dmastep(void)
 	u16int sa, da;
 	
 	sa = (reg[HDMASL] | reg[HDMASH] << 8) & 0xfff0;
-	da = (reg[HDMADL] | reg[HDMADH] << 8) & 0x0ff0;
+	da = (reg[HDMADL] | reg[HDMADH] << 8) & 0x1ff0 | 0x8000;
 	for(i = 0; i < 16; i++)
 		memwrite(da++, memread(sa++));
 	reg[HDMASL] += 16;