diff --git a/hw/ide/macio.c b/hw/ide/macio.c
index 5a326afd96449d57755f54f5be6e8d779e2fe6d0..76f97c25398d3e9ae801c9a5f192d3957f870664 100644
--- a/hw/ide/macio.c
+++ b/hw/ide/macio.c
@@ -273,6 +273,7 @@ static void pmac_ide_atapi_transfer_cb(void *opaque, int ret)
         s->io_buffer_size = MIN(s->io_buffer_size, io->len);
         dma_memory_write(&address_space_memory, io->addr, s->io_buffer,
                          s->io_buffer_size);
+        io->len = 0;
         ide_atapi_cmd_ok(s);
         m->dma_active = false;
         goto done;