PowerPC support

The PowerPC architecture, initially developed through the Apple, IBM, and Motorola alliance in the early 1990s, is a RISC-based processor design known for high performance and scalability. It was widely used in personal computers, workstations, embedded systems, and gaming consoles. Notably, PowerPC processors powered Apple Macintosh computers before their transition to Intel processors in 2006, as well as gaming consoles like the Nintendo GameCube, Wii, and Xbox 360, and continued use in network equipment and automotive systems.

PowerPC processors feature a clean RISC design that emphasizes high instruction throughput, efficient branch handling, and scalability. The architecture includes a rich set of registers, a powerful floating-point unit, and has evolved over time to support both 32-bit and 64-bit operations.

PowerPC64 support

The first 64-bit implementation of the PowerPC architecture was the PowerPC 620, introduced in the early 1990s. However, the first mass-produced 64-bit PowerPC processor aimed at mainstream usage was the Power3 while the first "small" 64-bit version for more compact and power-efficient applications was the PowerPC 970, introduced in late 2002. This processor, also known as the G5, was the first to combine a 64-bit architecture with a more consumer-friendly design, offering significantly higher performance, larger memory addressing capabilities, and greater precision for computational tasks.

Another key feature of the PowerPC architecture is its bi-endian nature, meaning it supports both little-endian and big-endian formats. This flexibility allows PowerPC processors to be adapted to various system requirements, as different applications and platforms may favor one format over the other. In little-endian mode, the least significant byte of a word is stored first in memory, commonly used in modern personal computers and architectures like x86 and ARM. Big-endian mode, where the most significant byte is stored first, was traditionally used in mainframe systems and older network protocols. This ability to switch between endianness was especially important for compatibility with different systems and devices, such as Apple's Macintosh computers and gaming consoles like the Nintendo GameCube, which used little-endian, while IBM’s PowerPC-based servers typically used big-endian mode.

While PowerPC’s prominence in personal desktop computing has waned with the rise of x86 processors, it continues to thrive in embedded systems, network equipment, and high-performance computing, particularly within IBM’s Power Systems servers. Its open design and support for a wide range of system configurations have allowed PowerPC to remain relevant in specialized and legacy applications.

Booting T2 Linux on Apple NewWorld PowerPC Macs via USB

Apple’s NewWorld PowerPC Macs lack first-class USB boot support in the graphical boot menu, likely due to Apple’s preference for FireWire—a technology it co-developed—and a reluctance to market or endorse USB as a boot medium. While USB booting is fully possible via manual Open Firmware commands, it was never integrated into the GUI, reflecting both technical limitations and strategic product positioning.

1. Write the ISO Image to USB

Download the appropriate T2 Linux PowerPC .iso image and write it 1:1 to a USB stick using dd or a similar tool:

dd if=t2-ppc.iso of=/dev/sdX bs=16k oflag=direct status=progress

Replace /dev/sdX with the correct device. Use lsblk under Linux, to find the correct path.

2. Boot via Open Firmware

Hold Command + Option + O + F during startup (or Ctrl + z in the GUI boot chooser) to enter the Open Firmware prompt. Then enter:

boot usb2/disk@1:,\:tbxi

Adjust usb2 as needed depending on your device and usb port, based on devices shown via dev / ls and devalias in Open Firmware.