[How to] Rom cooking
Extract NAND image files
I am new to android but not to linux. I used to tweak my winmo phone rom.
I have backed up my device with nandroid. I just need some explanations:
- why isn't the radio extracted?
- how can I "extract" does .img files to modify and then rebuild them?
I found some informations of what the .img files contain here: ROM Partitions it should be the same for Hero
I have found some informations on how to push updates to the rom by looking at modaco updates. It seems quite simple to delete/copy files on the hero rom using an update-sript file. I am however curious about the RSA cert and if some files need to be signed.
Any information welcomed.
To extract .img files, I have found unyaffs from http://code.google.com/p/unyaffs/
I have compiled it under ubuntu 64 (attached). Unyaffs works on system.img but on no other .img file
To extract boot.img use attached extract-kernel.pl and extract-ramdisk.pl
# extract-kernel.pl boot.img
# extract-ramdisk.pl boot.img
Should work for recovery.img but haven't tried as custom recovery images on the forum are great.
Seems you just need "to loopback mount an image on your linux box and format it with YAFFS".
But it is useless as because Hero's SPL does not allow flashing system.img directly. You should use an update.zip package for that. (read below)
After extracting your boot.img using attached extract-*.pl and tweaking it, in same folder run:
# mkbootfs boot.img-ramdisk | gzip > ramdisk-boot
# mkbootimg --kernel boot.img-kernel --ramdisk ramdisk-boot --cmdline "no_console_suspend=1 console=null" -o newBoot.img --base 0x19200000
Creating an update.zip package
Creating an update.zip package is quite easy in fact. For example, to add a (valid) test.apk package to your rom:
- create an empty folder <workdir>
- create folder structure for test.apk (<workdir>/system/app) and copy the test.apk
- create folder structure for update-script (<workdir>/META-INF/com/google/android)
- edit <workdir>/META-INF/com/google/android/update-script
- put in it:
show_progress 0.1 0
copy_dir PACKAGE:system SYSTEM:
set_perm_recursive 0 0 0755 0644 SYSTEM:app
show_progress 0.1 10
- compress the <workdir> content to zip (not the <workdir> folder itself)
Now you are going to sign the zip file. Download attached testsign.zip and copy it in your <SDK>/tools folder. Extract it here. It should create a sign subfolder with a testsign.jar file in it.
Then, from <workdir> folder, do:
java -classpath <SDK>/tools/sign/testsign.jar" testsign file.zip file-signed.zip
Ok, now your zip file is ready to be deployed using cyanogen recovery image.
To find more command to use in update-script, look at other's.
Modify .apk package
Seems it is easy to uncompress an .apk package (zip) an to modify files in it and then compress it. But after all: you must sign it like update.zip packages.
- What are those Odex files? Answer
- How to get rid of them?
Odex files depend on framework they are made for. To deodex an odex file use that how to
Then you may create a classes.dex file by executing the smali program on the "out" folder. You then rename it to classes.dex and add it to the .apk.
- How to create them?
Use dexopt-wrapper on device.
Porting an other device's rom
Well, that part is easy
- extract the system.img
- extract boot.img
- replace boot.img-kernel with the one from your stock Hero rom one.
- rebuild boot.img
- build update.zip package (look someone's hero custom rom to see how to do it)
- sign and flash
It should run place and make calls but probably won't have Wifi, BT, trackball support. If you make those work: tell me, but I think we should wait to be able to compile a 2.6.29 kernel to have those.
Androsign script (linux)
I wrote that androsign script to quick sign zip files. Just put it in your <SDK>/tools folder, then chmod +x. If you have put the tools folder in your PATH, you can call it directly like this:
androsign /dev/folder1/folder2/update.zip (or any zip/apk file)
It will output an update-signed.zip (or app-signed.apk etc) in the same folder than original file was in.
Thanks to every guy that helped me found all that.
I searched for hours, so I am more than happy to share it to save someone's time. I am just disappointed than some people here do not have that spirit: I could have use those hours for development instead of research...
So, if you found anything incorrect, would like to supply more informations or want to correct my bad english: just PM me.
- how to dump radio from device
- how to build a custom hero kernel (waiting for HTC sources)
How to prepare your own kitchen and useful scripts (linux)