diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index aa6059d2ad..fcbc1fd9d6 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -1982,7 +1982,7 @@ uint8_t sd_read_byte(SDState *sd)
 {
     /* TODO: Append CRCs */
     uint8_t ret;
-    int io_len;
+    uint32_t io_len;
 
     if (!sd->blk || !blk_is_inserted(sd->blk) || !sd->enable)
         return 0x00;
diff --git a/hw/sd/trace-events b/hw/sd/trace-events
index 96c7ea5e52..4140e48540 100644
--- a/hw/sd/trace-events
+++ b/hw/sd/trace-events
@@ -52,7 +52,7 @@ sdcard_unlock(void) ""
 sdcard_read_block(uint64_t addr, uint32_t len) "addr 0x%" PRIx64 " size 0x%x"
 sdcard_write_block(uint64_t addr, uint32_t len) "addr 0x%" PRIx64 " size 0x%x"
 sdcard_write_data(const char *proto, const char *cmd_desc, uint8_t cmd, uint8_t value) "%s %20s/ CMD%02d value 0x%02x"
-sdcard_read_data(const char *proto, const char *cmd_desc, uint8_t cmd, int length) "%s %20s/ CMD%02d len %d"
+sdcard_read_data(const char *proto, const char *cmd_desc, uint8_t cmd, uint32_t length) "%s %20s/ CMD%02d len %" PRIu32
 sdcard_set_voltage(uint16_t millivolts) "%u mV"
 
 # milkymist-memcard.c