diff --git a/drive.qcow2 b/drive.qcow2
new file mode 100644
index 0000000..c42dedc
Binary files /dev/null and b/drive.qcow2 differ
diff --git a/iso.json b/iso.json
new file mode 100644
index 0000000..cc0e6f4
--- /dev/null
+++ b/iso.json
@@ -0,0 +1,9 @@
+{
+    "iso9660": true,
+    "disksize": 16,
+    "initrd": { "type": "tar", "directory": "build/boot" },
+    "config": "bootparam.cfg",
+    "partitions": [
+        { "type": "boot", "size": 16 }
+    ]
+}
diff --git a/src/kernel.c b/src/kernel.c
index be2386e..62a8c2d 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -66,6 +66,7 @@ void _start() {
 }
 
 void virtio_cb(struct blk_req req, void *userdata) {
+    (void)userdata;
     char *type = NULL;
     switch (req.type) {
         case BLK_REQ_READ: type = "READ"; break;
@@ -77,7 +78,7 @@ void virtio_cb(struct blk_req req, void *userdata) {
     } else {
         uint8_t *p = pa_to_pointer(req.data);
         printlinef("%s done: %u sectors starting at %u", type, req.num_sectors, req.sector);
-        for (int i = 0; i < req.num_sectors; i++) {
+        for (uint64_t i = 0; i < req.num_sectors; i++) {
             printlinef("sector %u: %X8 %X8 %X8 %X8 ...", req.sector + i,
                 p[512*i], p[512*i + 1], p[512*i + 2], p[512*i + 3]
             );