diff --git a/src/random_mersenne_twister.c b/src/random_mersenne_twister.c
index 8b3b4afbe..6fdbb2e25 100644
--- a/src/random_mersenne_twister.c
+++ b/src/random_mersenne_twister.c
@@ -24,7 +24,7 @@
 
 static IWRAM_DATA u32 sStateArray[n] = {0}; // the array for the state vector
 static EWRAM_INIT s32 sStateIndex = n + 1; // index into state vector array, 0 <= state_index <= n-1
-static EWRAM_INIT s32 sTwistMatrix[2] = {0, a};
+static EWRAM_INIT u32 sTwistMatrix[2] = {0, a};
 
 void MersenneTwister_InitializeState(u32 seed)
 {