diff --git a/payloads/libpayload/drivers/usb/usbmsc.c b/payloads/libpayload/drivers/usb/usbmsc.c
index d39c784c30..8d5773629f 100644
--- a/payloads/libpayload/drivers/usb/usbmsc.c
+++ b/payloads/libpayload/drivers/usb/usbmsc.c
@@ -360,6 +360,9 @@ read_capacity (usbdev_t *dev)
 	}
 	printf ("  %d %d-byte sectors (%d MB)\n", MSC_INST (dev)->numblocks,
 		MSC_INST (dev)->blocksize,
+		/* round down high block counts to avoid integer overflow */
+		MSC_INST (dev)->numblocks > 1000000
+			? (MSC_INST (dev)->numblocks / 1000) * MSC_INST (dev)->blocksize / 1000 :
 		MSC_INST (dev)->numblocks * MSC_INST (dev)->blocksize / 1000 / 1000);
 }