diff --git a/include/layout.s b/include/layout.s
index 2ec1220..77aeef8 100644
--- a/include/layout.s
+++ b/include/layout.s
@@ -1,8 +1,15 @@
 %ifndef BOOT_LAYOUT_H
 %define BOOT_LAYOUT_H
 
-%define S1_ADDR 0x7c00
-%define S2_ADDR 0x8200
+%define S1_ADDR        0x7c00
+
+%define S2_DATA_LEN    32
+%define S2_TEXT_OFFSET S2_DATA_LEN
+%define S2_LOAD_ADDR   0x8200
+%define S2_DATA        S2_LOAD_ADDR
+%define S2_ENTRYPOINT  (S2_DATA_ADDR + S2_DATA_LEN)
+
+%define S3_LOAD_ADDR   0x10000
 
 ; %define MEMMAP          0x6a00
 ; %define MEMMAP_END      S2_ADDR
@@ -13,6 +20,6 @@
 %define REAL_GLOBALS_END 0x6a00
 %define REAL_STACK_BASE  REAL_GLOBALS
 
-%define S234_MAGIC 0x544e4150
+%define S2_MAGIC 0x544e4150
 
 %endif