diff --git a/demo/cdc_acm_msc_template.c b/demo/cdc_acm_msc_template.c
index 56f4c2a5..3f5e2fe7 100644
--- a/demo/cdc_acm_msc_template.c
+++ b/demo/cdc_acm_msc_template.c
@@ -112,7 +112,7 @@ void usbd_cdc_acm_out(uint8_t ep)
     uint32_t read_byte;
 
     usbd_ep_read(ep, data, 64, &read_byte);
-    for (uint8_t i = 0; i < read_byte; i++) {
+    for (uint32_t i = 0; i < read_byte; i++) {
         USB_LOG_RAW("%02x ", data[i]);
     }
     USB_LOG_RAW("\r\n");
diff --git a/demo/cdc_acm_multi_template.c b/demo/cdc_acm_multi_template.c
index eebd90c3..5f0dae6d 100644
--- a/demo/cdc_acm_multi_template.c
+++ b/demo/cdc_acm_multi_template.c
@@ -122,7 +122,7 @@ void usbd_cdc_acm_bulk_out(uint8_t ep)
     uint32_t read_byte;
 
     usbd_ep_read(ep, data, 64, &read_byte);
-    for (uint8_t i = 0; i < read_byte; i++) {
+    for (uint32_t i = 0; i < read_byte; i++) {
         USB_LOG_RAW("%02x ", data[i]);
     }
     USB_LOG_RAW("\r\n");
diff --git a/demo/cdc_acm_template.c b/demo/cdc_acm_template.c
index 05383877..d2b56f57 100644
--- a/demo/cdc_acm_template.c
+++ b/demo/cdc_acm_template.c
@@ -113,7 +113,7 @@ void usbd_cdc_acm_out(uint8_t ep)
     uint32_t read_byte;
 
     usbd_ep_read(ep, data, CDC_BULK_SIZE, &read_byte);
-    for (uint8_t i = 0; i < read_byte; i++) {
+    for (uint32_t i = 0; i < read_byte; i++) {
         USB_LOG_RAW("%02x ", data[i]);
     }
     USB_LOG_RAW("\r\n");