NRO is the executable format for non-ExeFS binaries.
It starts with the NRO-start structure then the "NRO" header and mainly describes .text, .rodata, and .data segments (like a short-form of ELF program headers):
NRO Start
| Offset
|
Size
|
Description
|
| 0x0
|
0x4
|
Unused
|
| 0x4
|
0x4
|
MOD0 offset
|
| 0x8
|
0x8
|
Padding
|
| Offset
|
Size
|
Description
|
| 0x0
|
0x4
|
Magic "NRO0"
|
| 0x4
|
0x4
|
NRO Format Version (Always 0)
|
| 0x8
|
4
|
size (Total NRO filesize)
|
| 0xC
|
0x4
|
Flags (Unused)
|
| 0x10
|
0x8 * 3
|
SegmentHeader[3] {.text, .ro, .data}
|
| 0x28
|
0x4
|
bssSize
|
| 0x2C
|
0x4
|
Reserved (Unused)
|
| 0x30
|
0x20
|
Value of "build id" from ELF's GNU .note section. Contains variable sized digest, up to 32bytes.
|
| 0x50
|
0x08
|
Reserved (Unused)
|
| 0x58
|
0x8 * 3
|
SegmentHeader[3] {.apiInfo, .dynstr, .dynsym}
|
| Offset
|
Size
|
Description
|
| 0x0
|
0x4
|
FileOffset
|
| 0x4
|
0x4
|
Size
|
Assets
This is an optional custom assets section for homebrew, this is located at file offset {NroHeader.size}. See also switch-tools for implementation.
The below offsets are relative to the beginning of the assets section (AssetHeader).
| Offset
|
Size
|
Description
|
| 0x0
|
0x4
|
Magic "ASET"
|
| 0x4
|
0x4
|
Format version, currently 0.
|
| 0x8
|
0x10
|
AssetSection icon. Used by the Homebrew Launcher. Like official icons, this is a 256x256 JPEG.
|
| 0x18
|
0x10
|
AssetSection NACP. Used by the Homebrew Launcher.
|
| 0x28
|
0x10
|
AssetSection romfs. Can be used by the application.
|
AssetSection
| Offset
|
Size
|
Description
|
| 0x0
|
0x8
|
Offset
|
| 0x8
|
0x8
|
Size, 0 indicates this section is empty.
|