# [App] [2.3+] OTA Verifier (beta)



## scary alien (Jun 25, 2011)

Mod Type:: Application

Difficulty:: Very Easy

Mod Status:: Beta

Apply In:: Other (See Description)

Requires Root:: No

Source:: 
Whenever there's an over-the-air (OTA) update sent-out or made available (either leaked or official), there's always a large number of users that end-up reporting that their installations have failed with the infamous and dreaded "E:Error in /sdcard/xxx.zip (Status 7) installation aborted." error message. So, I decided to try to write an app that would help folks figure-out what the issues might be so that they can get their OTA update installed.

The *OTA Verifier* app can be used to evaluate an over-the-air (OTA) update.zip or other flashable .zip file before you attempt the install or afterwards to help you figure-out why the installation may have failed. *OTA Verifier* will point-out what files and conditions are being tested so that you can more easily attempt to correct these issues.

*Play Market Link* (free!): OTA Verifier (beta)

*Do I have to be rooted to use this?*

No, but rooted devices will have more conditions that the app will be able to test/evalute because it will have access to protected files that non-app devices don't.

*Will the app actually do the installation or change anything on my device?*

No. The app will only evaluate the expressions and conditions contained inside the updater-script file inside the .zip file that's trying to be installed. None of the functions or commands that try to modify your device (i.e., delete/patch/format/extract, etc.) will be evaluated or executed. The app basically operates in "read-only" mode with respect to the .zip file being evaluated.

*Will this app work on older devices or flashable .zip files that use the amend update-script files?*

No, this app evaluates and interprets the newer edify updater-script files (notice the "r" in "updater").

*How do I use this app?* 
Install and launch the app
Click the "Select File" button and navigate to desired .zip file
Long-press (press and hold) the file entry for the desired .zip file
Click the "Verify OTA .zip" file pop-up
Wait for the app to process the file (should take under a minute, depending on your device)
View the displayed results (text will also be copied to the clipboard)

*Miscellaneous info:*

1. Savvy root users probably already know that after a failed .zip file installation, you should be able to view the /cache/recovery/log file to view the information about what might have failed. OTA Verifier will try to uncover all of the issues and not just the first one that causes the installation to fail.

2. While I wrote this app principally to evaluate OTA update.zip files, the edify updater-script files are used and written by ROM devs and others who created flashable .zip files. This app can be used to evaluate those file's updater-script files, too.

*How does this all work?*

Here's the basic outline/structure of what the app does:

1. the .zip file is selected by the user via the file selector

2. list of frozen system apps are identified for later reporting

3. the updater-script file is extracted from the META-INF/com/google/android folder in the .zip file

4. this updater-script file is parsed and converted into reverse polish notation (RPN) for execution

5. edify functions that might modify your device are NOT evaluated; these include apply_patch, delete, delete_recursive, format, mount, package_extract_dir/file, run_program, set_perm[_recursive], symlink, unmount, write_raw_image, etc.

6. note: the update-binary executable is not used by or involved in this app; the edify script interpreter that the app uses was written by me, in Java, specifically for this app

7. the remaining edify script functions that test conditions (such as apply_patch_check, apply_patch_space, assert, concat, file_exists, file_getprop, getprop, greater_than_int, if-then-else-endif, ifelse, is_substring, less_than_int, read_file, ui_print, and various operators (!, !=, &&, (, ), ;, ||, +, ==)) are evaluated using an operand/operator stack from the RPN expression parsed from the updater-script statements

8. expressions that fail (return a null-string) or are bypassed (usually because a resource (file/partition) is protected/secured against read-access) are reported for the user

9. after the entire script has been processed, the results are displayed in a pop-up window on the device and the text of those results are copied to the clipboard

*Planned / future features:*

- preferences / settings
- logging of the output to a file on the /sdcard
- test if .zip file is signed or not
- display more stats
- "explanation mode" to interpret, in English, what the edify commands are testing

*Successfully tested on:*

Samsung Galaxy Nexus (CDMA) 4.1.1
Samsung Galaxy Nexus (GSM) 4.1.2
Asus Nexus 7 tablet 4.1.2
Motorola Droid X 2.3.4

*The following edify commands/functions/operators are supported:*

*apply_patch_check* // apply_patch_check ( <filepath>, <sha1-checksum> [ , <sha1-checksum> ... ] )
// apply_patch_check ( <compoundvalue> )

<compoundvalue> := [ EMMC : <filepath> : <sha1-size> : <sha1-checksum> [ <sha1-size> : <sha1-checksum> ... ]
[ MTD : <dev-block> : <sha1-size> : <sha1-checksum> [ <sha1-size> : <sha1-checksum> ... ]
[ vfat : <dev-block> : <sha1-size> : <sha1-checksum> [ <sha1-size> : <sha1-checksum> ... ]

<dev-block> := filename in /dev/block

*apply_patch_space* // apply_patch_space ( <bytes> )
*assert *// assert ( <expression> ) 
*concat *// contact ( <string> , <string> )
*file_exists* // file_exists ( <filepath> )
*file_getprop* // file_getprop ( <filepath>, <propertyname> )
*getprop *// getprop ( <propertyname> )
*greater_than_int * // greater_than_int ( <integer>, <integer> )
*if then else endif *// if <condition> then <expression> [ else <expression> ] endif
*ifelse *// ifelse ( <condition>, <then-expression> [ <else-expression> ] )
*is_substring* // is_substring ( <string> , <string> )
*less_than_int* // less_than_int ( <integer>, <integer> )
*read_file * // read_file ( <filepath> )
*ui_print* // ui_print ( <string> ) parsed & executed, but output not displayed
*! * // logical NOT operator
*!=* // not equals operator
*&&* // logical AND operator
*(* // open paren: precedence / grouping 
*)* // close paren: precedence / grouping 
*;* // sequence/imperative (terminates & separates statements)
*||* // logical OR operator
*+* // string concatenation operator
*==* // equals operator
*#* // comment line

*The following command is not yet supported:*

sha1_check

*The following edify functions are NOT supported* (the majority of them because they are intended to modify your device):

apply_patch 
delete 
delete_recursive 
format 
mount 
package_extract_dir 
package_extract_file 
run_program 
set_perm 
set_perm_recursive 
symlink 
unmount 
write_raw_image 
is_mounted // innocuous, but not supported 
stdout // innocuous, but not supported 
show_progress // innocuous, but not supported 
set_progress // innocuous, but not supported 

*Keywords*:

OTA, over-the-air, updater-script, edify, amend

*Screenshots:*


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