Getting Started

There are two main general ways to install Tow-Boot. Installing to a dedicated platform firmware storage media, if your board supports it, or installing on shared storage.

To know whether your board supports the dedicated storage for the platform firmware, consult the documentation for your board.

On most boards supporting dedicated storage, it is possible to install using the shared storage strategy, but this is discouraged. The benefits of writing the firmware to dedicated storage far outweighs the drawbacks compared to using the shared storage strategy.

In all cases, once the firmware has been installed, continue to the Installing an Operating System section from this manual.

Dedicated Storage

This will use the automated menu-driven installer. Installing manually is also possible, but out of scope for this guide.

Learn about the CPU boot order of your board, and ensure no dedicated or shared storage has priority over the one you're going to use.

NOTE: If another Platform Firmware is present on the dedicated storage for your board, it is possible that it will have priority.

You may need to erase it, or do other manipulations on your board to skip it for a single boot.

After writing the firmware, the installer will report success, and depending, either reboot on any key input, or allow you to go back to the main menu, for the graphical installer.

Assuming the dedicated storage has priority, or that the SD card has been removed, it should now be booting in Tow-Boot from the dedicated storage.

You can now install a Linux distribution, without having to care about keeping the storage media formatted in a specific manner.

For SPI

Write the spi.installer.img file to an SD card or another valid storage media for your particular board.
```
 # dd if=spi.installer.img of=/dev/XXX bs=1M oflag=direct,sync status=progress
```
Boot the media on your board
Use the menu-driven interface to choose Flash firmware to SPI.

For eMMC Boot

Write the mmcboot.installer.img file to an SD card or another valid storage media for your particular board.
```
 # dd if=mmcboot.installer.img of=/dev/XXX bs=1M oflag=direct,sync status=progress
```
Boot the media on your board
Use the menu-driven interface to choose Flash firmware to eMMC Boot.

Shared storage strategy

This is called a strategy because we are making plans that we have to follow.

With this method, we write what amounts to a template disk image, which is already formatted in a controlled manner. The partition table is likely to be GPT formatted, but some SoC families force the use of MBR.

The disk will contain a partition, this partition serves to protect the platform firmware. It is important to know that with almost all SoC families you cannot move the partition. It may be possible to resize it, but the size has been chosen to allow further expansion if needed.

Write the shared.disk-image.img file to an SD card or another valid storage media for your particular board.
```
 # dd if=shared.disk-image.img of=/dev/XXX bs=1M oflag=direct,sync status=progress
```
Some partitioning tools require the secondary GPT to be at the end of the disk before attempting any operations. Grow the GPT partition to the physical size of the medium. (This operation is a no-op that forces a rewrite of the partition table.)
```
 # sfdisk --append /dev/XXX
```
Boot the media on your board

NOTE: When installing your operating system, make sure that you do not re-create the partition table from scratch, only edit the existing one. The Installing an Operating System section from this manual will remind you.

Using the shared storage strategy, you can simulate dedicated storage by not installing and using the storage media the platform firmware lives on.

Serial

Many AArch64 devices do not come with a display or can be used in headless mode (as an example - a small home server which doesn't need a display).

In those cases, using serial to interact with the device can be required. Especially before your operating system of choice is loaded.

Tow-Boot uses the same baud rate for all platforms and devices: 115200. This applies to all platforms, even those which generally default to another serial baud rate.

You can use the serial console software of your preference - screen , picocom , minicom and others.

Examples for connecting with serial

Examples to connect to the device while installing or booting Tow-Boot from another device:

$ screen /dev/ttyUSB0 115200
...
Press Ctrl+a and K to exit

$ picocom /dev/ttyUSB0 -b 115200
...
Press Ctrl+a and Ctrl+x to exit

$ minicom -D /dev/ttyUSB0 -b 115200
...
Press Ctrl+a and X to exit

To learn more, read the Differences from U-boot section.

Building Tow-Boot

This is not a getting started topic exactly. This is covered in the Development Guide section.