All those people who own a Nexus 7 tablet should be glad to know that there is a minor update launched for Jelly Bean which has a build number: JZO54K (Android OS V4.1.2 to be specific!). The below guide will help you to manually flash this update instead of waiting for Google to push it on your device:
Note: You will need a rooted Nexus 7 and ClockworkMod Recovery flashed on it.
Step#1: First of all download the Android 4.1.2 Jelly Bean (JZO54K) from this link.
Step#2: Locate it directly under /sdcard on your device’s storage.
Step#3: Now reboot your Nexus 7 into ClockworkMod (CWM) Recovery.
Step#4: At this point, select the “install zip from sdcard” option and then choose the file you located into your device in Step#2.
Step#5: Now leave the rest on ClockworkMod. Once done, choose “reboot system now” from the main menu interface.
Upon following the above guide, your Nexus 7 will boot into Android 4.1.2 Jelly Bean (JZO54K). If you are not sure, you can simply head over to the Settings > About and check for the software version.