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+# FSS0
+
+| Offset | Size     | Description                           |
+| ------ | -------- | ------------------------------------- |
+| 0x0    | 0x4      | Instruction to branch to startup code |
+| 0x4    | 0x4      | Offset of header                      |
+| 0x8    |          | Startup code                          |
+
+## Header
+
+| Offset | Size  | Description                          |
+| ------ | ----- | ------------------------------------ |
+| 0x0    | 0x4   | Magicnum "FSS0"                      |
+| 0x4    | 0x4   | Size of the entire file              |
+| 0x8    | 0x4   | Offset of startup code               |
+| 0xC    | 0x4   | Offset of content headers            |
+| 0x10   | 0x4   | Number of content headers            |
+| 0x14   | 0x4   | Maximum Horizon OS Supported         |
+| 0x18   | 0x4   | Atmosphere Version                   |
+| 0x1C   | 0x4   | First four bytes of the git revision | 
+
+## Content Header
+
+| Offset | Size  | Description       |
+| ------ | ----- | ----------------- |
+| 0x0    | 0x4   | Offset of content |
+| 0x4    | 0x4   | Size of content   |
+| 0x8    | 0x1   | Type              |
+| 0x9    | 0x1   | First flag        |
+| 0xA    | 0x1   | Second flag       |
+| 0xB    | 0x1   | Third flag        |
+| 0xC    | 0x4   | Reserved          |
+| 0x10   | 0xA   | Name              |
+
+### Content Header Types
+
+| Value | Description    |
+| ----- | -------------- |
+| 0x0   | Fusee Primary  |
+| 0x1   | Exosphere      |
+| 0x2   | LP0 Firmware   |
+| 0x3   | Reboot Stub    |
+| 0x4   | Sept Primary   |
+| 0x5   | Sept Secondary |
+| 0x6   | KIP            |
+| 0x7   | Bitmap         |
+| 0x8   | EmuMMC         |
+| 0x9   | Kernel Loader  |
+| 0xA   | Kernel         |
+
+### Content Header Flags
+
+| Value | Description  |
+| ----- | ------------ |
+| 0x0   | None         |
+| 0x1   | Experimental |