This is the procedure I used to compile CHDK (April 2007).

• Create a directory where to load the CHDK source code.

> mkdir ~/chdk && cd ~/chdk

• Get the CHDK source code.

> svn co https://tools.assembla.com/svn/chdk/trunk

or

> svn co https://tools.assembla.com/svn/chdk/branches/grand/

• Or update the source code

> cd grand && svn up

• Install the cross compiler

Get the sources of gcc and binutils from a GNU repository. I used the latest available version of each.

Decide where the cross compiler will be on your computer.

> mkdir ~/arm-elf

Tell your computer you are going to run programs from that location.

> export PATH=${HOME}/arm-elf/bin:$PATH

Create a working area and build binutils and gcc.

> mkdir ~/wa
 > cd ~/wa
 > tar xvfj ../src/rlx_dist/binutils-2.17.tar.bz2
 > tar xvfj ../src/rlx_dist/gcc-4.1.2.tar.bz2

> cd binutils-2.17
 > ./configure --srcdir=../binutils-2.17 --target=arm-elf \
     --prefix=~/arm-elf --disable-werror
 > make
 > make install
 > cd ..

Manually edit file <gcc-4.1.2/gcc/config/arm/t-arm-elf> to include the following lines without a "#" character in front of the line.

MULTILIB_EXCEPTIONS += *mapcs-26/*mthumb-interwork
   MULTILIB_OPTIONS    += mno-thumb-interwork/mthumb-interwork
   MULTILIB_DIRNAMES   += normal interwork

> mkdir gcc-4.1.2-arm-elf && cd gcc-4.1.2-arm-elf
 > ../gcc-4.1.2/configure --srcdir=../gcc-4.1.2 --target=arm-elf
     --with-cpu=arm9 --disable-libm --disable-libc --disable-threads
     --disable-nls --disable-libssp --disable-intl --disable-libiberty
     --enable-languages=c --with-softfloat-supp --with-float=soft
     --prefix=~/arm-elf
 > make
 > make install

That's it for the installation of the cross-compiler.

• Compiling the CHDK. Go to either 'trunk' or 'grand'.

> cd ~/chdk/grand

Manually edit file <makefile.inc> to select PLATFORM and PLATFORMSUB for your camera: just remove the "#" comment characters. Also, add the following line at the beginning of file <makefile.inc> to tell CHDK where the arm cross compiler is,

PATH := $(HOME)/arm-elf/bin:$(PATH)

You should be ready to compile everything.

> make fir

PS.FIR should be in the "bin" directory.

If you want to compile firmware for an another camera, just execute make with PLATFORM and PLATFORMSUB arguments. For example:

> make PLATFORM=a620 PLATFORMSUB=100f fir

To compile firmware for all cameras just type:

> make batch-zip

An alternative method with gcc-3.4.6 Edit

There is a patch included in HDK for building with gcc-3.4.6. It's a simpler install if you want to use this version of gcc. This method uses a global install of the arm-elf tools.

Remember to clear any CFLAGS you've got set:

> export CFLAGS=""

Compile and install binutils Edit

Extract the source, change to its directory, and

> mkdir binutils-2.17-arm-elf
 > cd binutils-2.17-arm-elf/
 > ../configure --srcdir=../ --target=arm-elf && make && sudo make install

Compile and install GCC-3.4.6 Edit

Download gcc-3.4.6, extract it and change to that directory. Patch the GCC source with the toolkit patch:

> patch -p0 < [path_to_hdk]/grand/tools/patches/gcc-3.4-arm.diff

Build the source:

> mkdir gcc-arm-elf
 > cd gcc-arm-elf/ 
 > ../configure --srcdir=../ --target=arm-elf --with-cpu=arm9 \
   --with-newlib --enable-multilib  --enable-languages=c \
   && make && sudo make install

You can now build the HDK source as directed above

Python GUIEdit

An GUI written in python is available here: chdk_linux drop

cd directory/where/chdk-linux-compiler-v*.py/is
python chdk-linux-compiler-v(version number here).py  example:(python chdk-linux-compiler-v1.py)

Click on "download env and trunk"
Uncomment your cameras row in "trunk/makefile.inc" (by default is s3is 100a enabled)
Click on "compile complete"

The files should be in "compiled_files"