diff --git a/src/drivers/pc80/tpm/tis.c b/src/drivers/pc80/tpm/tis.c
index 526b574..2b29acf 100644
--- a/src/drivers/pc80/tpm/tis.c
+++ b/src/drivers/pc80/tpm/tis.c
@@ -172,7 +172,7 @@
 
 static inline void tpm_write_data(u8 data, int locality)
 {
-	TPM_DEBUG_IO_WRITE(TIS_REG_STS, data);
+	TPM_DEBUG_IO_WRITE(TIS_REG_DATA_FIFO, data);
 	write8(TIS_REG(locality, TIS_REG_DATA_FIFO), data);
 }