Acer A500 ICS 4.0.3 Official Firmware.

Acer A500 ICS official Firmware 

HoneyComb 3.2.1 & Ice Cream Sandwich Official 4.0.3 Acer A500 Tablet Firmware.

Acer_A500_7.014.01_GEN1: ICS for Acer A500

Acer_A500_7.014.1_GEN1: HoneyComb for Acer A500

How to install:

1-Download above linked File to desktop .  

2-Unzip the file using winrar or winzip . You will find update.zip folder inside. 

3 - Copy the update.zip on a micro sd. 

4 - Now enter in recovery mode and choose install from Sd card.  

5 - Select "Yes" and wait for installation start. 

6-Perform wipe concerned or only when the start is going to throw FC's for the launcher and others. 

7 - Using complete / update package:

If you have an error opening the zip file, use Acer decryter update to decrypt the file, and try to open it again.Files downloaded from "cdn.acer.futuredial.com" has to be deciphered by exemple. 

After that, you have to extract the update.zip from it, put it on your external SD card (not working in internal memory) and boot your tablet with Vol-and power. The update will run automatically with the default recovery, not CWM with button. 

Source : xda-developers