[ZenFone 2 General] jopframos:
[IMG="Asus Zenfone 2"]https://www.asus.com/websites/global/products/Lk0Sg1Ulh0Ph49Hl/v6/img/index/p2_3.9mm.png[/IMG]

Caution: I'm not responsible for any damage that can occur trying my methods in your devices. Just proceed if you're an advanced user and conscious about what I'm doing here. Read this again. And again.

Hello. I've been searching a lot about this and after searching in lots of russian/chinese forums I've found that inside boot.img there is a config_init.sh file that loads phone's configuration depending on the phone's SKUID and many other parameters:

Attempt #1 - Change config_init.sh file

# software configuration related boot actions
#please sync to RF BAND
FULL_BAND=8
WW_BAND=0
TW_BAND=1
CN_BAND=2
US_BAND=3
TR_BAND=4
TEST_BAND=12
# ZX550ML RF BAND
WW_US_BAND=15
TW_CN_JP_BAND=0
WW_TEST_BAND=1
TW_TEST_BAND=8

# project ID
ZE550ML=23
ZE551ML=31
ZR550ML=28
ZX550ML=27
ZE551ML_CKD=30

RFSKUID_DETECT=$(cat /sys/module/intel_mid_sfi/parameters/rf_sku_id)
PROJID_DETECT=$(cat /sys/module/intel_mid_sfi/parameters/project_id)
COUNTRY_CODE=$(cat /factory/PhoneInfodisk/country_code)

log -p i -t config_init "PROJID: $PROJID_DETECT ,RFSKUID: $RFSKUID_DETECT"

if [ -n "$PROJID_DETECT" ]; then
case $PROJID_DETECT in
"$ZE550ML" | "$ZE551ML" | "$ZE551ML_CKD")

if [ "$COUNTRY_CODE" = "TH" ]; then
echo "V1_DSDA_ZE550ML_TH" > /config/local_config

elif [ -n "$RFSKUID_DETECT" ]; then
case $RFSKUID_DETECT in
"$FULL_BAND")
echo "V1_DSDA_ZE550ML_FULL" > /config/local_config
;;
"$WW_BAND")
echo "V1_DSDA_ZE550ML_WW" > /config/local_config
;;
"$TW_BAND")
echo "V1_DSDA_ZE550ML_TW" > /config/local_config
;;
"$CN_BAND")
echo "V1_DSDA_ZE550ML_CN" > /config/local_config
;;
"$US_BAND")
echo "V1_DSDA_ZE550ML_US" > /config/local_config
;;
"$TR_BAND")
echo "V1_DSDA_ZE550ML_TR" > /config/local_config
;;
"$TEST_BAND")
echo "V1_DSDA_ZE550ML_TEST" > /config/local_config
;;
*)
echo "V1_DSDA" > /config/local_config
;;
esac
else
echo "V1_DSDA" > /config/local_config
fi
;;
"$ZX550ML")
if [ -n "$RFSKUID_DETECT" ]; then
case $RFSKUID_DETECT in
"$WW_US_BAND")
echo "V1_SINGLE_ZX550ML_WW" > /config/local_config
;;
"$TW_CN_JP_BAND")
echo "V1_SINGLE_ZX550ML_WW" > /config/local_config
;;
"$WW_TEST_BAND")
echo "V1_SINGLE_ZX550ML_WW" > /config/local_config
;;
"$TW_TEST_BAND")
echo "V1_SINGLE_ZX550ML_WW" > /config/local_config
;;
*)
echo "V1_SINGLE_ZX550ML" > /config/local_config
;;
esac
else
echo "V1_SINGLE_ZX550ML" > /config/local_config
fi
;;
*)
echo "V1_DSDA" > /config/local_config
;;
esac
else
echo "V1_DSDA" > /config/local_config
fi

CONFIG_PATH=/local_cfg
PROPS_FILE=init.props

# Get selected software configuration

config=`cat /config/local_config`
mount -o bind /system/etc/catalog/$config /local_cfg

log -p i -t config_init "Activating configuration $config"

# Set properties for the selected configuration

# read all FeatureTeam's init.props file
for f in /local_cfg/*/init.props
do
while read l; do

# Ignore empty lines and comments
case "$l" in
''|'#'*)
continue
;;
esac

# Set property
setprop `echo ${l/=/ }`

done < $f
done

Based on this I expect we can change it in a way we can load WW information and so unlock LTE bands.

Update #1
#RFSKUID_DETECT=$(cat /sys/module/intel_mid_sfi/parameters/rf_sku_id)
RFSKUID_DETECT=$WW_BAND # this will set RFSKUID_DETECT=0

Changelog:

Update #1: Without changing RFSKUID it will load configuration as if it was WW version;

Attempt #2 - Change XML files

Change this file content /system/etc/catalog/V1_DSDA_ZE550ML_CN/telephony_config/V1_DSDA_ZE550ML_CN_726x.xml
In line where is mentioned (4g_active_bands) change bands to the wanted bands, as well as in the next 3 lines. Below there are 2 images to help you.

V1_DSDA_ZE550ML_WW_726x.xml example

[img="WW"]http://blog.8796.jp/8796kanri/files/2015/05/image1.png[/img]

V1_DSDA_ZE550ML_CN_726x.xml example

[img="WW"]http://blog.8796.jp/8796kanri/files/2015/05/image4.png[/img]

Changelog:

Update #1: Change 4G bands in XML file;

In order to unpack/repack boot.img you can use this great tool: http://xdaforums.com/showthread.php?t=2319018

As my Zenfone 2 (CN) didn't arrive yet I cannot start testing this yet.

I expect you to help me discussing about this and replying with your opinions, if this is or not a good way or something else..

Best wishes

João Ramos