October 19, 2003

Building Linksys WRT54G images from source

That’s my goal today. Linksys released source for their WRT54G among other access points that run Linux. I’m going to attempt to build an image.

I grabbed the 1.42.2 firmware version, which oddly they don’t have an image up for on their site yet. Read the top level README.TXT and followed its instructions up to type 'make dep' at which point it failed:

/nfs/verin/array0/home/darkness/tmp/wrt54g/WRT54G/release/src/linux/linux/scripts/mkdep -D__KERNEL__ -I/nfs/verin/array0/home/darkness/tmp/wrt54g/WRT54G/release/src/linux/linux/include -Wall -Wstrict-prototypes -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common -fomit-frame-pointer -I /nfs/verin/array0/home/darkness/tmp/wrt54g/WRT54G/release/src/linux/linux/include/asm/gcc -G 0 -mno-abicalls -fno-pic -pipe    -nostdinc -iwithprefix include -- offset.c > .depend
realpath(/nfs/verin/array0/home/darkness/tmp/wrt54g/WRT54G/release/src/linux/linux/include/asm/gcc) failed, No such file or directory
make[2]: *** [fastdep] Error 1
make[2]: Leaving directory `/nfs/verin/array0/home/darkness/tmp/wrt54g/WRT54G/release/src/linux/linux/arch/mips/tools'
make[1]: *** [_sfdep_arch/mips/tools] Error 2
make[1]: Leaving directory `/nfs/verin/array0/home/darkness/tmp/wrt54g/WRT54G/release/src/linux/linux'
make: *** [dep-files] Error 2

(No effort made to wrap the above, sorry.) It looks like it wants asm/gcc. There is include/asm-mips/gcc and include/asm-mips64/gcc. So I’ll just ln -s asm-mips include/asm and… that seems to have fixed the above error. So we’re moving on.

While my machine is running make dep I’ll go ahead and mention that the default configuration for the kernel it builds is in arch/mips/defconfig-bcm947xx. Also, check out WRT54G/release/src/router/rc for a good time. Lots of interesting stuff in there that I’m guessing is performed on boot by the Linksys. Since I’m giving out links, http://www.seattlewireless.net/index.cgi/LinksysWrt54g is a great source for information on this device, including information on how to stick a serial console on it and some promising-sounding TFTP stuff.

So now make dep is done, and I’m on to make in the release/src directory (per instructions).

Now that’s chugging so I have more time to talk. It looks like Broadcom basically makes this whole device for Linksys, more or less. Linksys brands it and ships it out, basically. All the stuff here that was made by anyone appears to have been made by Broadcom, except for maybe the “ASP” files (HTML)… which were probably made by Broadcom and hacked on just enough by Linksys to make it look like theirs. In release/src/router/config (I think) there’s what looks like a hacked-up kernel menuconfig for configuring features on the Broadcom device.

I will now wait patiently (yeah right) for this to complete. I hope ccache is doing its thing. Cache misses increasing along with files in cache/cache size. (Thanks Nightwolf for telling me about watch. Try watch -d -n 1 ccache -s.)


mipsel-uclibc-ld -r -o .pppoecd magic.o fsm.o lcp.o ipcp.o
upap.o pppoehash.o pppoe_client.o libpppoe.o main.o auth.o options.o
demand.o utils.o sys-linux.o pppoe.o md5.o chap.o md4.o chap_ms.o
/opt/brcm/hndtools-mipsel-linux/bin/mipsel-linux-ld: cannot open
/home/darkness/usr/lib/libcrypt.a: No such file or directory
make[2]: *** [pppoecd] Error 1
make[2]: Leaving directory
make[1]: *** [ppp] Error 2
make[1]: Leaving directory
make: *** [all] Error 2

Now where did it get that path? I’m able to run make from WRT54G/release/src/router and get the same result. Somewhere in there something is defaulting to my home directory. Ah, $(TOOLCHAIN) is coming out to be /home/darkness, probably because I’ve got the ccache links for the compilers in /home/darkness/ccache-bin and it appears to assume the toolchain root is the parent of that directory. Set TOOLCHAIN for both mipsel-linux and mipsel-ulibc and we’re in business again. Build continues. Actually, I’m going to make clean then make again just in case those bad paths were mucking anything up.

Oops, to make clean make sure you have RCS installed. It uses /usr/bin/rcsclean. make again and a bunch of stuff goes by real fast. The real test of whether ccache was working or not. (It was. Duh.)

[darkness@verin release]$ ls -l image
total 5588
-rw-------    1 darkness darkness  2855936 Oct 19 16:01 code.bin
-rw-rw-r--    1 darkness darkness  2854912 Oct 19 16:01 linux.trx

Voila. Now I don’t know if I have the balls to flash it. I wonder if I can TFTP boot it.

Comments (1)

  1. May 22, 2005

    Hey, thanks! That was just what I needed. Seriously, my wife hates this Linux stuff and has GOT to have her 802.11g. You saved me much marital discord.