Here is a article share to you about update pumpkin android unit from 4.2 to 4.4, he bought this android car Stereo 4.2 from us.

BEFORE UPGRADING YOUR UNIT
Upgrading is supposed to be a safe operation, but you never know what can happen. So, before updating make sure that:
1- you have a backup of your system (the easiest way is download nandroid root from google play, and do a nandroid backup with TWRP format)
2- make sure you can enter in bootloader mode (see below how to)
3- it is recommended to backup your apps and data (use titanium from google play). The update will do a factory reset.

FIRMWARES ARE NOT 100% COMPATIBLE BETWEEN UNITS

Do a back up of your internal SD card memory. It will be wiped during the process.

I wrote you some basic instructions of rooting and upgrading bellow. (my sources are English forum: http://forum.xda-developers.com/showthread.php?t=2660662 and Russian forum: http://4pda.ru/forum/index.php?showtopic=557670&st=60 )

How to Root

Prerequisite

Check in `Settings > About`, Android version must be 4.2 (or bellow), it will not work with 4.4 KitKat (or not with this method)

Instructions

* On the device, download `Root Master 2.1.1` on this URL: Root_Master_2-1-1.apk

* Make sure internet connection is active, `Root Master` downloads instructions depending on the device you have

* Open `Root Master`, refuse the update (last version of root master will not work)

* Click the big button where it is written “ROOT”

* Wait, it will ask you to install an app, install it (otherwise it will keep you asking that)

* Wait again, at the end a message popup, click the purple left button, it will reboot the device and install SuperUser (right button is for rating)

* Your device is Rooted !

Pretty easy !

How to flash (include update to 4.4.2 KitKat)

Prerequisite

* Backup your internal SD card, it will be wiped up in the process

* Different manufacturer, have their own MCU, so we need to find out which manufacturer made the device we have, go to `Settings > About`, check at the MCU version, it will start by something like this: `MTCB-KGL`, `MTCB-KLD`, `MTCB-GS`, `MTCB-RM`, `MTCB-JY`. The device I ordered was a `Klyde`, with KLD written after `MTCB`, so I will need to use the `KLD` MCU.

(* If you want to go back to your original version, write down, the firmware version number you have in `Settings > About`)

* Download the MCU corresponding to your device (in my case `KLD`), you can find it there in the `MCU Only` folder: https://drive.google.com/folderview?id=0BxmzvLRI7-eNeVA2SWkwM1pLZ28&usp=sharing#listv

* Download the Android version you want (same link), `Custom` versions are already Rooted, `Official` versions are the one from the manufacturer

Instructions

* Extract those rar/zip, and copy `mcu.img` and `update.img` at the root of a micro SD card (formated in FAT32)

* Put this micro SD card in the GPS slot of your device

* A message will pop-up at the screen saying an upgrade has been found, just ignore it, and restart your device (using a needle in the little hole)

* At the restart the same message will pop-up again, this time, accept the Upgrade

* The device will reboot and install the upgrade, wait until the update is finished

Troobleshooting

* I didn’t need to do that, but with KitKat, If you don’t have access to Internal SD anymore, just go to `Settings > Storage` and erase it

* For any other issues, use this feed: http://forum.xda-developers.com/showthread.php?t=2660662

And as extra a little picture of your product installed in my car with a custom skin (sorry for quality, it was night) :

By Jérémy

Do a back up of your internal SD card memory.

How to root and update pumpkin Android head unit from 4.2 to 4.4?