diff --git a/initrd_fs.z80 b/initrd_fs.z80
index 79f4c61..96dfd12 100644
--- a/initrd_fs.z80
+++ b/initrd_fs.z80
@@ -1,7 +1,7 @@
 .global _start
 _start:
 call get_free_mailbox ; Get a mailbox
-push hl
+ld (mailbox_num), hl
 ld de, 1
 call get_free_frame ; Set up a frame to send messages at 0x8000
 ld b, c
@@ -81,8 +81,6 @@ adc a, 0
 ld c, a
 jp initrd_read_loop
 call proc_map_set ; Register ourselves as ID 1
-pop hl
-ld (mailbox_num), hl
 msg_loop:
 call yield
 ld hl, (mailbox_num)