[Android Q&A, Help & Troubleshooting] cracktech:
Flashing instructions

[Apologies for the lengthy reply, I have to assume that you have no experience in flashing MTK SoC]

Sorry to hear that! I am also contemplating t buy a Chinese Android headunit with GPS but I am still contemplating. Reason being which model to buy? I am an avid Lenovo devices fan because in my part of the world models from Lenovo uses a lot of MTK SoC. (Any other other brand I buy is also a must to be on MTK SoC)

Ok! Now based on your short description I saw "scatter.txt" file mentioned so it is definitely an MTK devices, 100%.. When you boot loop you definitely will not be able to access any function, more so with a head unit that dont provide hardware buttons. I can only help you understand the method to reflash the firmware on MTK devices the rest you have to figure it out yourself.

The USB port is your key here. If the manufacturer did not provide you with USB "IN" (female) port which is not normal and only provide you with USB connectors you will have to decode/or just connect the wiring from the connectors to a USB female Port (which what China manufacturers do at the back of the head unit). There are also head units that provide ready to use USB port on the facia.

Whatever it is I cant tell you which port to use. This where you will have to experiment yourself.

Download MTK flashing tool "SP Flashtool" (find the ones that is suitable upto MTK device 6592 because it should be back ward compatible with older devices) The Chinese dont use the latest MTK SoC for their head units, that is only reserved for the high end heads.

Read up on how to install SP Flashtool on your PC and other accompanying Drivers you have to install, (if you only have a Mac go borrow somebodys Win7 or Win10 PC) there are no Mac SPFlashtool.

Once you have install according to SPFlashtool instructions you read. (It has to follow a certain sequence) e.g "1- ADB Driver" so on and so forth because if you dont follow the sequence it might fail to start the flashing operation. (You will not know it but I am pretty damn sure you will be cussing me).

First read up on how to install ADB driver for MTK devices correctly. Confident? Now try connecting your device to the PC experimenting to identify the correct USB port to use. If the ADB is installed correctly and you got the right USB from the device connected your PC wil give an audible sound( it should unconnected to condition evreytime you test). OK good connection! Only then try installing SP Flash tool and try a dry running the SPFT. If your installation is correct there should be either color changes to the SPFT window because it doesnt detect any devices.

You are good to go! Your MTK Android device should be in the "OFF" condition (after every shutdown there are still some operation running in the background,so it is a good practice to wait at least 5 seconds for it to be 100% OFF.) Run the SPFT fully loaded with the firmware dislayed in the SPFT window. Then initiate "Download" (make sure all indicators is at "download only" do not change this option or you are gonna have a really dead duck.) At this point the SPFT is active and waiting for you to attach the device to PC (before running make sure the PC and device is not connected yet!). If everything is per instructed ADB, USB Cables/Ports, SPFlashTool (download only) you will see color lines in the SPFT Window, wait till the end of process it will display notificatio. If the firmware is correct and you have attached and 12V DC source to the device it should boot up as fresh as new.(provided that the supplier gave you the correct firmware).

A word of advise these cheap head units normally bluff their actual Android version e.g actual KitKat advertised and displayed as Marshmallow. Best of luck!

The zip file attached are screenshots of the flashing process.