ARM7
| Name | Region base | End | Size | Mirrored | Width / modes |
| BIOS (ARM7) | 0x00000000 | 0x00003FFF | 16 KB | no | unknown |
| Main RAM | 0x02000000 | 0x023FFFFF | 4 MB (8 MB) | yes | 16 / all |
| Shared RAM | 0x037F8000 | 0x037FFFFF | 32 KB | ? | 32 / 16,32 |
| Private RAM | 0x03800000 | 0x0380FFFF | 64 KB | yes | 32 / 16,32 |
| Registers | 0x04000000 | * | * | * | * |
| Wifi Control | 0x04800000 | 0x04800FFF | * | yes** | 16 |
| Wifi MAC memory | 0x04804000 | 0x04805FFF | 8 KB | yes** | 16 |
| GBA cart ROM | 0x08000000 | 0x09FFFFFF | 32 MB | no | 16 / all |
| GBA cart RAM | 0x0A000000 | 0x0A00FFFF | 64 KB | yes | 8 / 8 |
The ARM7 BIOS is protected via a PC check. The portion below PROTECTION_CR? can be read when PC < PROTECTION_CR?, and the portion beyond it can be read when PC < 0x4000.
ARM9
| Name | Region base | Size | Mirrored | Width / modes |
| ITCM | 0x00000000* | 16 KB | no | 32 / all |
| DTCM | 0x00800000* | 16 KB | no | 32 / all |
| Main RAM | 0x02000000 | 4 MB (8 MB) | yes | 16 / all |
| Shared RAM | 0x03000000 | 32 KB | yes | 32 / 16,32 |
| Registers | 0x04000000 | * | * | * |
| Palette RAM | 0x05000000 | 2 KB | yes | 16 / 16,32 |
| Video RAM | 0x06000000 | ? | ? | 16 / 16,32 |
| Sprite RAM | 0x07000000 | 2 KB | yes | 16 / 16,32 |
| GBA cart ROM | 0x08000000 | 32 MB | no | 16 / all |
| GBA cart RAM | 0x0A000000 | 64 KB | yes | 8 / 8 |
| BIOS (ARM9) | 0xFFFF0000 | 4 KB | no | unknown / all |
The Main RAM is always available to both processors, although one has priority over it, and the other will be delayed if both try to access it at the same time.
The 'shared' RAM actually consists of two banks of 16 KB each, and either one only available to a single processor at a time. They can be switched back and forth, to implement a buffer passing scheme for e.g. wireless packets or a sound buffer.
ITCM and DTCM can be relocated using the system control coprocessor CP15
The ARM9 BIOS provides a handful of functions, but does little in the way of system setup. It clears some memory, then waits for the ARM7 bios to signal that system init is complete.