tomato-migrate

README

tomato-migrate

Background

There are two methods to save/restore configurations on a router with the Tomato firmware installed. These methods however are meant to be used on the same router, but there are situations where one might want to restore to a different router. For instance, the original router might have a hardware failure and no longer powering on.

The first method involves dumping the nvram and restoring specific keys. This method is however not user-friendly and requires an understanding of what each configuration variable does, which is something that even most power users may not fully grasp.

The other method involves using the backup/restore menu in the GUI, which generates a .cfg file. A Tomato .cfg file is a gzipped (compressed) text file which store settings using the null byte (\0) as the end-of-line symbol. For this reason, it is not always straightforward to open and edit, especially on Windows systems.

With both methods, it is not possible to restore using the entire file as-is, as some of the settings, namely hardware MAC address mappings, are hardware-dependent. We can read through the nvram backup and restore the settings one by one, ignoring those pertaining to MAC addresses, but that manual process is tedious and error-prone. We can manually edit the Tomato .cfg file by uncompressing it and opening it in an appropriate text editor, but this is not user-friendly and error-prone.

tomato-migrate targets the more user-friendly .cfg restore method, and enables restoring to another Tomato of the same model and firmware.

Installation

On systems with a recent version of go installed, go install can be used.

go install github.com/hsn723/tomato-migrate@latest

Pre-compiled binaries are also available in the Releases page.

Usage

tomato-migrate -i FILE -o FILE

The following assumes you are in a disaster recovery situation where the original router no longer works and you are aiming to restore an existing .cfg backup (referred to as old.cfg going forward) to a new Tomato router of the exact same model and firmware.

• Perform a fresh install of Tomato on the new router
• Download a backup of the new router's configuration (referred to as new.cfg going forward)
• Run tomato-migrate providing it with the paths to old.cfg and new.cfg, with old.cfg as the input and new.cfg as the output
  • Example: `tomato-migrate -i old.cfg -o new.cfg
• tomato-migrate will
  • Create a backup of new.cfg
  • Read new.cfg and get a list of the new hardware MAC addresses
  • Read old.cfg and remap MAC addresses to those of new.cfg
  • Write the resulting configuration to new.cfg
• You can now upload the resulting new.cfg to the new Tomato router to restore the old router's configuration