JRO03S is the latest Android 4.1 Jelly Bean official build for Nexus 7 which is in-built in current devices of Nexus 7 but for older devices you will have to flash using Clockworkmod Recovery. XDA Senior Member jamesst20 has made it possible to install JRO03S ROM on Nexus 7.
The guide mentioned below is only for ASUS Nexus 7 and cannot be used on any other device.
We cannot be held liable for any loss or damage done to your device while following the guide.
Install JRO03S Android 4.1 Jelly Bean ROM on Nexus 7
Take a complete backup of data,apps and settings as the procedure may wipe your data.
Make sure that the battery of device has a minimum charge of 60%.
Enable “USB debugging” on your device by going to Settings >> Developer options >> Enable USB debugging.
Bootloader on your device should be unlocked. You can do that by using by using Nexus Root Toolkit.
Install ClockworkMod recovery on your device.
Download JRO03S ROM from here. Copy the zip file to SD-Card of your device without extracting.
Switch off device and enter into recovery. Press and hold the Volume Up and Volume Down and Power buttons.
Take a Nandrop backup of your current ROM. Select Backup and Restore option from the recovery mode and then select backup again.
Select the option “wipe data/factory reset” and confirm to wipe all data. Wait till data gets wiped.
Select “install zip from sdcard” and then select “choose zip from sdcard”. Go to the ROM file on the SD card which you have installed in the earlier step and select to install.The ROM will start installing.
Select “go back” and then select “reboot system now”.