diff --git a/trunk/src/boards/rt-01.cpp b/trunk/src/boards/rt-01.cpp
index 2c0591c0..b6363794 100644
--- a/trunk/src/boards/rt-01.cpp
+++ b/trunk/src/boards/rt-01.cpp
@@ -26,6 +26,8 @@
 
 #include "mapinc.h"
 
+extern u64 xoroshiro128plus_next(); // deterministic random
+
 static DECLFR(UNLRT01Read) {
 //	u16 i, prot_areas[2][2] = {
 //		{ 0x8E80, 0x8EFF },
@@ -33,7 +35,7 @@ static DECLFR(UNLRT01Read) {
 //	};
 	if(((A >= 0xCE80) && (A < 0xCF00)) ||
 	   ((A >= 0xFE80) && (A < 0xFF00))) {
-		return 0xF2 | (rand() & 0x0D);
+		return 0xF2 | (xoroshiro128plus_next() & 0x0D);
 	} else
 		return CartBR(A);
 }