PUMPKIN CAR STEREO SUPPORT CENTER

Yes my pumpkin/kylde unit is struggling to handle the newer updated apps, I'm thinking of the px6 4gb ram, however pumpkin are just a reseller so any "brand" will do for me. However i still have the same unit from 2015 and it's still bearable but not on the factory rom. The best info on th...

Check this post it will point you in the right direction
viewtopic.php?f=20&t=1027

I remember a while back that someone with the same unit did it and it worked how well I'm not sure .. but I know it was a kld unit , this is basically the mcu on the unit , this is all from memory so don't take it a gospel , I think mcu version kld 2.85 and lower are for 4.4 defined as a mtcb unit, ...

If it's a kld unit it's been done ...

Also according to the link provided to you , you need a higer mcu version for 5.1.1 kld5 version 2.97 upward it looks as though mtcc is basically 5.1.1 sorry I can't be more accurate as I did mine over a year ago

Plus the highest I've seen on these units is 5.1.1 ... honestly I had all the headaches to start with, my unit came with really buggy software. Just keep flashing software unitll you find what works for you

You should be doing it from the recovery menu by holding down the power button for like 15secs
Make sure your file has the correct name and stored in the root of the sd or usb

Here is all the info and links you should need https://forum.xda-developers.com/wiki/Hui_Fei_Type

Bare in mind screen resolution .Just make sure you keeps roms to mtcb/mtcc .. and mcu's to kld .. it doesn't matter what version

Same software though you can use any mcu version that is kld and any software that is mtcb or mtcc you would be better Google searching

https://forum.xda-developers.com/wiki/Hui_Fei_Type this will give you all the info links to mcu and firmwares you could ever need