Difference between revisions of "FIRM"
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A structural example of a FIRM file (created using the specs in [https://github.com/3dshax/ctr ctrtool]) can be found [http://depositfiles.com/files/lzpo8yqyo here] (Note it does not contain any ARM code, it's just a structural example) | A structural example of a FIRM file (created using the specs in [https://github.com/3dshax/ctr ctrtool]) can be found [http://depositfiles.com/files/lzpo8yqyo here] (Note it does not contain any ARM code, it's just a structural example) | ||
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| + | The ARM9 section contains the ARM9 kernel and the ARM9 process. The ARM11 section(s) contains the ARM11 kernel, and the ARM11 process(es). For NATIVE_FIRM/SAFE_MODE_FIRM these ARM11 processes are sm, fs, pm, loader, and pxi. Normally the 4th section is not used. The code loaded from FIRM is constantly running on the system until another FIRM is launched. | ||
== FIRM Header == | == FIRM Header == | ||
Revision as of 21:57, 31 March 2013
Overview
This is the file format for the 3DS' Firmware, it contains four 'sections' of ARM code (ARM9 and ARM11). The firmware sections are not encrypted in the FIRM format.
A structural example of a FIRM file (created using the specs in ctrtool) can be found here (Note it does not contain any ARM code, it's just a structural example)
The ARM9 section contains the ARM9 kernel and the ARM9 process. The ARM11 section(s) contains the ARM11 kernel, and the ARM11 process(es). For NATIVE_FIRM/SAFE_MODE_FIRM these ARM11 processes are sm, fs, pm, loader, and pxi. Normally the 4th section is not used. The code loaded from FIRM is constantly running on the system until another FIRM is launched.
FIRM Header
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 4 | Magic 'FIRM' |
| 0x004 | 4 | Reserved1 |
| 0x008 | 4 | ARM11 Entrypoint |
| 0x00C | 4 | ARM9 Entrypoint |
| 0x010 | 0x030 | Reserved2 |
| 0x040 | 0x0C0 (0x030*4) | Firmware Section Headers |
| 0x100 | 0x100 | RSA-2048 signature of the FIRM header, using SHA-256. |
Firmware Section Headers
| OFFSET | SIZE | DESCRIPTION |
|---|---|---|
| 0x000 | 4 | Offset |
| 0x004 | 4 | Address |
| 0x008 | 4 | Size |
| 0x00C | 4 | Firmware Type ('0'=ARM9/'1'=ARM11) |
| 0x010 | 0x020 | SHA-256 Hash of Firmware Section |