The ZyXEL NR7101 prepend an additional header to U-Boot images. This header use the TRX magic 0x30524448 (HDR0), but is incompatible with TRX images. This code is reverse-engineered based on matching 32 bit numbers found in the header with lengths and different checksum calculations of the vendor images found on the device. The result was matched against the validation output produced by the bootloader to name the associated header fields. Example bootloader validation output: Zyxel TRX Image 1 --> Found! Header Checksum OK ============ZyXEL header information================== chipId : MT7621A boardId : NR7101 modelId : 07 01 00 01 kernel_len : (14177560) kernelChksum : (0x8DD31F69) swVersionInt : 1.00(ABUV.0)D1 swVersionExt : 1.00(ABUV.0)D1 Zyxel TRX Image 2 --> Found! Header Checksum OK ============ZyXEL header information================== chipId : MT7621A boardId : NR7101 modelId : 07 01 00 01 kernel_len : (14176660) kernelChksum : (0x951A7637) swVersionInt : 1.00(ABUV.0)D0 swVersionExt : 1.00(ABUV.0)D0 ================================================= Check image validation: Image1 Header Magic Number --> OK Image2 Header Magic Number --> OK Image1 Header Checksum --> OK Image2 Header Checksum --> OK Image1 Data Checksum --> OK Image2 Data Checksum --> OK Image1 Stable Flag --> Stable Image1 Try Counter --> 0 Image1: OK Image2: OK The coverage and algorithm for the kernelChksum field is unknown. This field is not validated by the bootloader or the OEM firmware upgrade tool. It is therefore set to a static value for now. The swVersion fields contain free form string values. The OEM firmware use ZyXEL structured version numbers as shown above. The strings are not interpreted or validated on boot, so they can be repurposed for anything we want the bootloader to display to the user. But the OEM web GUI fails to flash images with freeform strings. The purpose of the other strings in the header is not known. The values appear to be static. We assume they are fixed for now, until we have other examples. One of these strings is the platform name, which is taken as an input parameter for support other members of the device family. Signed-off-by: Bjørn Mork <bjorn@mork.no> |
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config | ||
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package | ||
scripts | ||
target | ||
toolchain | ||
tools | ||
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BSDmakefile | ||
Config.in | ||
COPYING | ||
feeds.conf.default | ||
Makefile | ||
README.md | ||
rules.mk |
OpenWrt Project is a Linux operating system targeting embedded devices. Instead of trying to create a single, static firmware, OpenWrt provides a fully writable filesystem with package management. This frees you from the application selection and configuration provided by the vendor and allows you to customize the device through the use of packages to suit any application. For developers, OpenWrt is the framework to build an application without having to build a complete firmware around it; for users this means the ability for full customization, to use the device in ways never envisioned.
Sunshine!
Development
To build your own firmware you need a GNU/Linux, BSD or MacOSX system (case sensitive filesystem required). Cygwin is unsupported because of the lack of a case sensitive file system.
Requirements
You need the following tools to compile OpenWrt, the package names vary between distributions. A complete list with distribution specific packages is found in the Build System Setup documentation.
binutils bzip2 diff find flex gawk gcc-6+ getopt grep install libc-dev libz-dev
make4.1+ perl python3.6+ rsync subversion unzip which
Quickstart
-
Run
./scripts/feeds update -a
to obtain all the latest package definitions defined in feeds.conf / feeds.conf.default -
Run
./scripts/feeds install -a
to install symlinks for all obtained packages into package/feeds/ -
Run
make menuconfig
to select your preferred configuration for the toolchain, target system & firmware packages. -
Run
make
to build your firmware. This will download all sources, build the cross-compile toolchain and then cross-compile the GNU/Linux kernel & all chosen applications for your target system.
Related Repositories
The main repository uses multiple sub-repositories to manage packages of
different categories. All packages are installed via the OpenWrt package
manager called opkg
. If you're looking to develop the web interface or port
packages to OpenWrt, please find the fitting repository below.
-
LuCI Web Interface: Modern and modular interface to control the device via a web browser.
-
OpenWrt Packages: Community repository of ported packages.
-
OpenWrt Routing: Packages specifically focused on (mesh) routing.
Support Information
For a list of supported devices see the OpenWrt Hardware Database
Documentation
Support Community
- Forum: For usage, projects, discussions and hardware advise.
- Support Chat: Channel
#openwrt
on freenode.net.
Developer Community
- Bug Reports: Report bugs in OpenWrt
- Dev Mailing List: Send patches
- Dev Chat: Channel
#openwrt-devel
on freenode.net.
License
OpenWrt is licensed under GPL-2.0