Mediagate MG35

 

MG35BYOF

Page history last edited by Vasile 5 mos ago

 

BYOF - Simplified firmware builder

BYOF is a PC tool to created your own firmware.

Version: 2.0

Status: Stable

 

 

  1. BYOF - Simplified firmware builder
  2. Description
    1. Directories
    2. Scripts
      1. 00-startup
      2. mkskin
      3. mktarget
      4. mkupgrade
      5. 99-finished
    3. Utilities
      1. palfixup.py
      2. mg35tool
      3. mkcramfs
    4. Settings
  3. Download
    1. Thanks
  4. Comments

 

 

Description

 

In order to simplify the development of custom firmwares that can be upgraded quickly and simply to reflect MediaGate releases, you can use the BYO firmware package and scripts. Included are a skin patcher, a user/developer target builder, and an upgrade packager. These tools are currently targeted for Linux, but a Windows port is planned.

 

Directories

 

The standard BYO package contains 3 sub-directories to store files used for patching the stock firmware:

 

  • skin.Fixups contains all the files needed to change the skin of the firmware: a copy of the stock palette (in stock_v1.act), the royalblue new palette and the new skin images.
  • cram.FixupsUser contains the changes from the stock firmware to create end-user firmware. By default, this is empty. If you choose to apply a skin to your firmware, mkskin will add the custom dvdplayer.bin and img subdirectory here .
  • cram.FixupsDevel contains the changes from the stock firmware to create developer firmware. Like for cram.FixupsUser, if you choose to apply a skin mkskin will add custom dvdplayer.bin and img subdirectory .

 

During the build process, the following directories will/might be created, depending on your settings:

 

  • cram.Stock will be created by 00-startup. The stock firmware cramfs image will be mounted here as a base for your custom firmware.
  • cram.User will be created by mktarget if you set MODAUDIENCE=User in the settings file. This is where your custom user firmware image will reside during the build process.
  • cram.Devel will be created by mktarget if you set MODAUDIENCE=Devel in the settings file. This is where your custom developer firmware image will reside during the build process.

 

Scripts

The BYO firmware builder contains 5 scripts to reduce the manual modifications necessary for building a custom firmware:

  • 00-startup
  • mkskin
  • mktarget
  • mkupgrade
  • 99-finished

 

For best results, the scripts should be executed in that order. After the scripts have successfully executed, you should be left with a new .upgrade file. Its name depends on the stock firmware version you used as a base, and various settings.

 

00-startup

 

This startup script ensures you have a stock .upgrade file (downloading one if necessary), extracting the contained cramfs, and mounting it. To run it, simply use ./00-startup. This script can be run multiple times, but you should really only need to run it once. NOTE: Downloading requires the 'wget' utility.

 

mkskin

 

The mkskin script handles the modification of the stock dvdplayer.bin for applying a new theme, and puts the result in your cramfs target folder. It also copies any files located in skin.Fixups/ to the cramfs target folder. If you run mkskin more than once, be sure to re-run mktarget and mkupgrade to regenerate your .upgrade file.

 

mktarget

 

The mktarget scripts creates a new target cramfs folder, and populates it with a copy of the stock firmware image, as well as the contents of the cramfs fixup directory. It then performs a number of transformations based on your settings.

 

mkupgrade

 

The mkupgrade script extracts the linux.gz kernel image from the stock upgrade, creates a cramfs image from your target directory, and glues them together into your final .upgrade file.

 

99-finished

 

This cleanup script unmounts and deletes the stock firmware image, and removes the cramfs target and stock folders. This should always be run after you finish working on your target .upgrade.

 

Utilities

Along with the above scripts, there are a few extra utilities included that are required by the scripts:

  • palfixup.py
  • mg35tool
  • mkcramfs

 

palfixup.py

The palfixup utility directly handles the patching of dvdplayer.bin with a new palette.

 

Usage:

palfixup [<arguments>]

 

 

Arguments:

{-s <stockdvd.bin> | --stockdvd=<stockdvd.bin>}

Identify the location of the stock dvd player to fix up with a new palette.

{-p <stockpal.act> | --stockpal=<stockpal.act>}

Identify the location of the stock palette to replace with a new palette.

{-o <customdvd.bin> | --output=<customdvd.bin>}

Identify the location to save the updated dvdplayer binary to.

{-c <custompal.act> | --output=<custompal.act>}

Identify the location of the updated palette to replace the old palette.

 

 

Example/Defaults:

palfixup  -s cram.Stock/dvdplayer.bin   -p skin.Fixups/stock_v1.act -c skin.Fixups/royalblue.act  -o cram.Fixups/dvdplayer.bin

 

 

mg35tool

The mg35tool handles the splitting and joining of upgrade files.

 

 

mkcramfs

The mkcramfs utility creates a cramfs image from a directory. The basic command line is as follows:

 

 

mkcramfs <sourcedir> <destcramfs.img>

 

Settings

 

The settings are located in the settings file in the root of the BYO distribution. Each of the above scripts references these settings for determining how and what to do.

 

Name

Description

Default

LANG

Language identifier.

Eng

STOCKVERSION

Which stock .upgrade version to use.

1.5.1

STOCK_ROOT

The directory to create and mount the stock cramfs.img on.

cram.Stock

MODAUDIENCE

The target audience of the .upgrade to build. Can be User or Devel.

User

MODVERSION

The trailing version number to append to STOCKVERSION in naming the upgrade.

4

MODRELEASE

The release identifier for your upgrade.

alpha4_sf24

MODDER

The modifier tag for your upgrade.

JD

TARGET_ROOT

The base directory name for building your target cramfs. MODAUDIENCE will be appended after a '.'

cram

SKIN_ROOT

The source of the skin fixups. Your skin files should be in a subdirectory, with the palette in this directory.

skin.Fixups

SKIN

The name of the skin to apply.

royalblue

USE_SOFT

Create soft links (1) or hard links (0) for various executables.

1

USE_RBIN

Relocate executables (1) to /sbin/rbin in the target cramfs.

0

USE_BBREL

Create relative (1) or absolute (0) links to busybox.

1

USE_INTMK

Use the internal (1) or system-wide (0) mkcramfs to build the target image.

1

USE_NEWNBT

Use the original (0) or new (1) nbtscan.

0

USE_PARTRWRO

Keep (1) the ro1/ro2/rw1/rw2 partition-specific remounters.

0

USE_BIGBOX

Use the BIGbox (1) or standard busybox (0) for applets.

0

USE_ORGBAK

Create backups of bin,etc. in org (1) or not (0)

0

 

Download

 

You can obtain the latest version of the BYO firmware package here.

 

Thanks

Special thanks to gadgetmind, pbarette, icabrindus, teddystacker, and everyone else whose hard work make working around MediaGate much more palatable.

 

Comments

(VasileB) idea: place all the binaries from / and /bin to /org/rbin (for "root bin") and /org/bin respectively, and place symlinks in their original place pointing to the new locations. Now if you want to override one of the programs in /bin using unionfs, you can do that and still have access to the original application. (e.g. replacing /bin/nbtscan with a wrapper, which can still later call the original /org/bin/nbtscan). You can also replace the built-in players, but losing access to the original ones.

 

(VasileB) one more convoluted step, only for the root programs: place all the binaries from in the root directory to /org/rbin, as before. Now create a new directory /rbin and place in it symlinks to the programs in /org/rbin. Now create symlinks in / to the previously created symlinks from /rbin. What you have now is a symlink chain as in this example: /fileplayer.bin --> /rbin/fileplayer/bin --> /org/rbin/fileplayer.bin. The result is that you can override any of the / programs using unionfs over /rbin, while keeping access to the original programs in /org/rbin. A possible application is to create a new wrapper /rbin/fileplayer, which to parse the beginning of the .m3u files. If it's a "normal" m3u, call the original /org/rbin/fileplayer.bin. If it's a m3u file having an url as target, call the radio player. This way we can extend any of the built-in players, including /dvdplayer.

 

(John) How about just link root binaries into /bin, and if you want to keep them, move them (eg. to /bin/real) before you delete them?

(John) Alternatively, if no moving is desired, we could add a mirror of /etc, /bin, /sbin, etc. under /org in the cramfs, but leave the originals untouched (no symlinking). They would always be at a known location, take up very little space in RAM/cramfs, and require no modifications to target application locations.

(VasileB) Can you mirror the files in the cramfs, so they don't waste space? Something like a hardlink? That solves first ppart of the problem, the access to original files. But in order to override them, you need to have symlinks in / which point to another place you can unionfs upon (e.g. /bin, as you suggested), since you cannot unionfs the root directory. The only thing to test is if /dvdplayer works with symlinks in /, instead of real files.

(John) dvdplayer.bin (and the rest) work fine as symlinks.

 

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