Glossary
The terms the documentation uses.
| Term | Meaning |
|---|---|
| ADT | Apple Device Tree, the device-tree format XNU boots from; mkadt.py writes it (Device tree) |
| AFE | the audio front end, MediaTek’s block between memory and the codec |
| A-die | the radio chip of the MT6631 combo chip, which picks the rails and firmware flavour |
| ATF | Arm Trusted Firmware: runs at the secure level; its memory is one of LK’s reservations |
| boot-arg | a word on the kernel’s command line; Open Mapple’s start with mp_ (catalogue) |
| boot-args record | the next boot’s command line, kept in the root partition so iOS can write it (record) |
| BROM | the boot ROM: MediaTek’s first stage, and the download mode used to unbrick with mtkclient |
| BTIF | the SoC’s UART-like interface to the Bluetooth side of CONNSYS |
| CCIF, DPMAIF | the mailbox and packet interfaces between the application processor and the modem |
| CONNSYS | MediaTek’s connectivity subsystem: Wi-Fi, Bluetooth and the like, with its own CPU and firmware |
| DVFS | dynamic voltage and frequency scaling |
| EMI MPU | the memory protection unit in the memory interface; it faults accesses from the application processor to reserved ranges |
| hole | a range of DRAM XNU must not touch (Memory map) |
| IPSW | the iOS restore file; the build downloads the iPhone X’s for the user |
| LK | “Little Kernel”, MediaTek’s bootloader; Open Mapple leaves it stock |
| LUN | a UFS logical unit; the user data is LUN 2 on the realme 8i |
| LVTS | the SoC’s thermal sensors (Thermal) |
mka, lunch | the build commands, as in Android’s tree (Build targets) |
mtkloader | the loader LK starts; it chooses between XNU and Android |
| OPP | operating performance point: a frequency and voltage pair |
| payload | the kernel, device tree and default boot-args in one file (Payload) |
| PMIC | the power-management chip; on the realme 8i an MT6366 with the MT6358’s register layout |
| SCP | the sensor hub’s processor (Sensors) |
| safe boot | holding Volume Down at the loader’s window: the payload’s own settings, no record (Install guide) |
| shim | the program that acts as iBoot for XNU: places the kernel, device tree and boot_args |
| SPU | Apple’s sensor processor, whose HID services MappleSPU.cpp stands in for |
| SSPM | a power-management microcontroller on the SoC |
| STP | the transport that carries WMT, Wi-Fi and Bluetooth packets to CONNSYS |
| UFS | the phone’s flash storage |
xnusys | the partition of our own: the root image, carved from userdata |
| XNU | Apple’s kernel |
Applies to Release 1 · Updated 15 November 2026