Android stuck on bootloop after adding apk files in system.img ROM

I have a stock ROM and I need to add new pre-installed apps to it. Actually it is an Android Head Unit that has a ROM called Full AOSP on MStar Cedric3. well, this is how the file tree inside firmware's zip may look:

[/script]
boot.img
system.img.lzo
userdata.img.lzo
AN6Q03 Version.txt
DEVINFO_EMMC_SZDEMO_MST786_DDR1G.bin
MCU.bin
MPEG.bin
PQ.bin
RTK_cedric.bin
auto_update.txt
auto_update_nand.txt
auto_update_nor_and_nand.txt
bakupdata.img.lzo
cahce.img.lzo
cedric_ROM.bin
certificate.img
logo.bmp
ramdisk.img
readme.txt
recovery.img
sdcard4G.img
update_nor.txt

I have searched and googled that in order to add or remove pre-installed apps you need to go through system/apps folder and work in it. so, in order to add my apps to the ROM I use Android Kitchen by dsixda. These are the steps:

1. setup working folder
2. unpack system.img.lzo to system.img
3. extract system.img with Android Kitchen
4. add my apps into /system/apps folder
5. repack system.img.lzo again and replace the old one inside the ROM
6. copy all files in the working folder onto microSD(because device won't update if I only put zip file)

following the instruction given by the official site's readme, I press power+home button together to update NAND with all the ROM contents inside my microSD, when updating process finish, device CAN'T REBOOT and stuck on complete progress screen. When i restart, device on and completely stuck at boot logo.

I try to unpack my ROM again, this time i let the original system.img and add my apps into userdata.img.lzo file. when i repeat all those steps and device complete updating from my micro SD, it can REBOOT, pass boot logo, but stuck at boot animation screen.

I have read from some sources also they said that this BOOTLOOP occurs because the Android cannot comunicate properly between its components including apks.

so, what should I do friends? to add my apps as pre-installed apps inside the stock ROM so I can distribute this ROM to be installed on similar Car Head UNit devices... Thanks

Additional Information: Inside script folder there are a lot of scripts for example inside file [[system script it looks like this

# <- this is for comment / total file size must be less than 4KB
fatload mmc 0 0x45000000 system.img.lzo
emmc erase.p system
dcache on
icache on
emmc unlzo 0x45000000 $(filesize) system  1
dcache off
icache off
% <- this is end of file symbol

I also cannot create backup or update.zip using either Titanium Backup or NAndroid backup, they always make empty file...