diff --git a/src/drivers/spi/flashconsole.c b/src/drivers/spi/flashconsole.c
index 654177f6d3..d5c4382101 100644
--- a/src/drivers/spi/flashconsole.c
+++ b/src/drivers/spi/flashconsole.c
@@ -75,7 +75,8 @@ void flashconsole_tx_byte(unsigned char c)
 
 	size_t region_size = region_device_sz(rdev_ptr);
 
-	line_buffer[line_offset++] = c;
+	if (line_offset < LINE_BUFFER_SIZE)
+		line_buffer[line_offset++] = c;
 
 	if (line_offset >= LINE_BUFFER_SIZE ||
 	    offset + line_offset >= region_size || c == '\n') {