diff --git a/writeimg.c b/writeimg.c
index 45422be..25304e1 100644
--- a/writeimg.c
+++ b/writeimg.c
@@ -94,9 +94,9 @@ int perform_write(write_job_t *job) {
 
     while (1) {
         ssize_t read_file = read(file_fd, job->buffer2, job->block_size);
-        ssize_t read_block = read(block_fd, job->buffer, job->block_size);
+        ssize_t read_block = read(block_fd, job->buffer, read_file);
 
-        assert(read_block >= read_file);
+        assert(read_block == read_file);
         assert(read_block >= 0);
         assert(read_file >= 0);