I'll start off by dropping a link to a tutorial showing & explaining the official way of resetting family settings. This works for unmodded and modded 360 consoles and is most certainly the safest way. I suggest using this method:



These methods only apply to modded 360s.

Requirements:
- Windows computer
- Your console's nand
- Your console's cpukey
- Jrunner with Extras
- A way to move your nand file back and forth from the console to pc and vice versa [USB/FTP].

Method 1 - Using the nomobile feature via Jrunner with Extras:

1) To be safe, start by making a backup of your current nand. The easiest way is to use Simple nand flasher, run its xex and make sure to DUMP/BACKUP your nand. Once dumping is complete you can exit simple nand flasher.
2) Copy flashdmp.bin from simple nand flasher and paste it onto your computer.
3) Open Jrunner, Load Source, Load your flashdmp.bin file. This should contain your console's cpukey.
4) Under the XeBuild group box and Options tab, hit Advanced XeBuild Options. Next, you want to tick the option that says nomobile. Afterwards, hit OK.
5) Go back to the Home tab under XeBuild. Confirm the exploit being used is correct. Jrunner normally auto selects the correct one for you when you load in flashdmp. Also have the latest kernel 17559 selected.
6) Create XeBuild. Once the nand is rebuilt you should see XeBuild Finished. Have a nice day. At this point you want to copy your rebuilt nand back into the Simple nand flasher folder on your console. So hit "Show working folder" and that will open a folder to where your rebuilt nand is "updflash.bin"
7) Move updflash into the simple nand flasher folder on your console & run the flasher. This time you're FLASHING/WRITING the nand so follow the on screen instructions to do that.
8) When the flashing is complete, Simple nand flasher will auto-reboot your console but I suggest powering down and replugging your power cable when the nand write completes to be sure the nand was overwritten.
9) Boot up the console and you should be in its initial setup if you did everything correctly. Parental controls/family settings are now removed.

Method 2 - Getting the unique reset code via Jrunner with Extras:

1) Follow the first 3 steps from Method 1 and then proceed here:
2) Click on the "Nand" dropdown menu in Jrunner and then select SMC Config Editor
3) Now you will see the reset code for your console. In order to use this, go into Console Settings on the Xbox, select System Info, and then enter your reset code/sequence as fast as you could. If done correctly you will get a pop up asking if you want to reset the settings.