Unable to install CyanogenMod on Galaxy S2 i777 I'm trying to use ROM Manager to install the cm-10.1.3 ROM on my phone, but I'm getting the following error (from recovery.log):

-- Installing: /sdcard/bluetooth/cm-10.1.3-i777.zip
Finding update package...
I:Update location: /sdcard/bluetooth/cm-10.1.3-i777.zip
Opening update package...
Installing update...
Warning:  No file_contexts
script aborted: assert failed: getprop("ro.product.device") == "i777" || getprop("ro.build.product") == "i777" || 
   getprop("ro.product.device") == "SGH-I777" || getprop("ro.build.product") == "SGH-I777" || 
   getprop("ro.product.device") == "SGH-S959G" || getprop("ro.build.product") == "SGH-S959G"
assert failed: getprop("ro.product.device") == "i777" || getprop("ro.build.product") == "i777" || getprop("ro.product.device") == "SGH-I777" || getprop("ro.build.product") == "SGH-I777" || getprop("ro.product.device") == "SGH-S959G" || getprop("ro.build.product") == "SGH-S959G"
E:Error in /sdcard/bluetooth/cm-10.1.3-i777.zip
(Status 7)
Installation aborted.
result was NULL, message is: assert failed: install_zip("/sdcard/bluetooth/cm-10.1.3-i777.zip")


Here's info about my phone:

Model number:     SAMSUNG-SGH-I777
Android version:  4.1.2
Baseband version: I777UCMD8
Kernel version:   3.0.31-1154545-user
                  se.infra@SEP-126 #3
                  SMP PREEMPT Tue Apr 23 22:10:17 KST 2013
Build number:     JZO54K.I777UCMD8
Recovery:         ClockworkMod 6.0.1.0


In addition, I found this set of instructions http://wiki.cyanogenmod.org/w/Install_CM_for_i777, but using ROM Manager seems to be a much easier way to install the ROM. These instructions say to use the wipe data/factory reset option in CWM recovery - does this mean I should use the "Wipe Data and Cache" pre-installation option in ROM Manager?
From the CyanogenMod Wiki:


  "Status 7" Error
  I have a stock AT&amp;T Galaxy S2 (i777) which had been updated to the latest version of Android from AT&amp;T. I followed the instructions for installing CM 10.1 but received the following error:

assert failed: getprop("ro.product.device") == "i777" || 
getprop("ro.build.product") == "i777" || 
getprop("ro.product.device") == "SGH-I777" || 
getprop("ro.build.product") == "SGH-I777" || 
getprop("ro.product.device") == "SGH-S959G" ||
getprop("ro.build.product") == "SGH-S959G"
E:Error in /sdcard/cm-10.1.3-i777.zip (Status 7) Installation aborted.

  
  I tried updating to the very latest version of ClockworkMod Recovery, but that didn't help. The solution I found was to edit the "updater-script" file located at cm-10.1.3-i777.zip\META-INF\com\google\android. I removed the first line from that file which was performing the assert and getprop statements. I was certain I have an i777, so I was pretty sure that removing this line would be ok. After removing this line of code I pushed the CM zip file to my phone and was then able to install ok.
  
  This page was last modified on 3 December 2013, at 22:42.


So if you are 100% positive that you have an i777, then you can follow these steps:


extract the update package zip file
navigate to */META-INF/com/google/android
open updater-script in a text editor like notepad++
remove the first line that does the "assert" checks. 
zip the folder back up, using only "store", no compression.