diff --git a/src/iodev.c b/src/iodev.c
index 1dba18a2..8125be26 100644
--- a/src/iodev.c
+++ b/src/iodev.c
@@ -33,7 +33,7 @@ size_t con_rp[IODEV_MAX];
 ssize_t iodev_can_read(iodev_id_t id)
 {
     if (!iodevs[id]->ops->can_read)
-        return false;
+        return 0;
 
     return iodevs[id]->ops->can_read(iodevs[id]->opaque);
 }
diff --git a/src/usb_dwc3.c b/src/usb_dwc3.c
index 935ef82f..d4fe90eb 100644
--- a/src/usb_dwc3.c
+++ b/src/usb_dwc3.c
@@ -1368,11 +1368,11 @@ size_t usb_dwc3_read(dwc3_dev_t *dev, cdc_acm_pipe_id_t pipe, void *buf, size_t
 ssize_t usb_dwc3_can_read(dwc3_dev_t *dev, cdc_acm_pipe_id_t pipe)
 {
     if (!dev || !dev->ready)
-        return false;
+        return 0;
 
     ringbuffer_t *host2device = dev->pipe[pipe].host2device;
     if (!host2device)
-        return false;
+        return 0;
 
     return ringbuffer_get_used(host2device);
 }