ROM / Firmware/ Brick Recovery for 7" Android Head Unit AC8227l YT9217 YT9218 1/16GB
Thanks everyone who contributed in my effort to fix my bricked device. Here is all that I have found useful in successfully reviving my device.
The files shared here are the ones that worked on my unit (see specs and pictures below) If your device is different, it may or may not work.
If the device has dedicated radio chip inside, the Firmware number will show as YT9218, if no radio chip, then it will show as YT9217 Note: if your device is not bricked, Make a full backup before trying another firmware.
Preloader (Boot_1) from other Similar Firmwares: (Link)
Download the one similar to your device's version.
Firmware via flash tool: Rooted TWRP 20190523 (Link) Thanks Maxkir
(You may need to remap side touch buttons in Factory settings (code 8888) -> Touch settings -> Click start -> Name of the button -> The button itself ->Repeat for all the buttons -> close -> ok).
Firmware for YT9213 Device: (Link) (Thanks pajurpl)
Memory Dump Procedure via flashtool:
(Memory dump is only needed if you need full recovery from a backup. Otherwise you may only need to do the next part.)
Download and install MTK drivers. (Link)
Load scatter file and preloader (Link) in spflashtool. Press Ctrl Alt V , then go to Window and select "write memory". In file path select "user", in begin address put 0x0, In Region select the partition named "EMMC_USER". Hit Write memory. After that plug in the usb cable (connected to usb1 port). If the device is not detected, you need to power it on. If still not detected then you might need to short the two test points (see picture) (without power this time) and then plug in the usb cable. Remove the short when write process starts. Check if the issue is fixed. If its not fixed, then do the same to write boot2 and boot1 partitions as well. You may need to download Boot_1 specific to your original firmware from the link above.
Uploading Firmware (full or parts) via flashtool:
If you are uploading the firmware available in parts, you only need to upload "BOOTIMG" and "ANDROID" (SYSTEM).
You may also need to flash "RECOVERY". Remember to uncheck the preloader. Here is a nice instructions file. (Link) (thanks Maxkir)
There is more info and firmwares to chose from at 4pda forum.
Update / Upgrade Procedure via USB flash drive:
Copy the zip file (do not extract) to usb drive or microSD card, (formatted by SD Card Formatter). Connect to usb port 1 or 2. Go to Car Settings, System info. Click Android Upgrade.
Extract the zip into a folder named XYAUTOUPG into the flash drive or microSD card, connect to usb port 1 or 2 and then reboot. Upgrade should start automatically. You might need to try with different USB drives or sd cards. For some reason this only works with certain usb and cards.
MCU Upgrade Procedure via USB flash drive:
Extract the mcu file into flash drive or microSD card. Connect to usb port 1 or 2. Go into system info and update mcu.
Make a Full Backup/Memory Dump:
Open SPFlashtool, Select Memory Test Tab, Select only RAM Test (uncheck the rest), push start, and connect the unit. Save the information appeared, in a text file for later. (Read above "Memory dump procedure" for the usb connection setup).
Now go to ReadBack Tab, Double click on empty space next to tick mark, Select a folder where you want to store the dump file, and Type a name for the dump file you are going to creat, (ie. Boot_1, Boot_2, USER). Click Save. In next window "Readback block start address", select the region you want to make backup of (ie. EMMC_BOOT_1, EMMC_BOOT_2, EMMC_USER).
Start address is 0x0000000000000000
Length copy and paste from the text file you created earlier.
typically for Boot_1 and 2 the length is 0x0000000000400000
and for USER (16GB models) the length is 0x00000003a8000000
Now click on Readback and then connect the unit via usb cable. and Read process will start.
Do the same to make backup of all three partions. USER will take long time because its the largest partition.
RDS FM Radio:
Radio app with fixed RDS, channel names on buttons and HiFi: (Link) (thanks sjguk)
Copy to FMRadio directory, rename to FMRadio.apk and change permission 764. (or 755 ?).
Channel name Editor: (Link) (thanks mclaught)
install as normal. You may need to install GalaPublicResources. Click top right dots.
Multi Window Mode:
Go to root folder, look for build.prop. Open in text editor. Change the line ro.build.type=user to ro.build.type=userdebug.
If no such line is there, then simply add the line at the end. Save and exit. Go to Android settings, Developer options, look for multi window mode and enable it. Swipe down from the top of the window, Click on recent apps tile. You'll see the new multi window option there.
Subwoofer output Pin:
The default AUX_out pins are for mid range audio and is controlled by Mid slider in the mixer. The subwoofer output is on another pin (See Picture).
it is easy to remove one of the AUX_out pin and install it at the Sub output. this pin is controlled by Subw slider in the audio mixer.
motherboard marking YT9217 VER1.5 XY AUTO also 9218 VER2.4 XY AUTO near the antenna
Model no 8227L_demo android 8.1
DDR 1GB FLASH 16GB
CPU A7 1.3GHzx4
Amplifier AC7315 mos bile duct 45Wx4
AutoChip ARM AC8227L
Kingston EMMC 16G
All relevant info about ROMs and flashing you can find in top header of this russian forum.
Look at the spoilers in the gray header layer and use Google translate to understand what is written there.
There are 3 ROM versions for the 8227L based head units. I downloaded and installed the oldest of the 3 (rooted and TWRP IMG included). Copy all files from the RAR to a flashdrive in root folder.
Turn off the head unit.
Connect the flashdrive to USB 1 slot of the head unit.
Turn on the the head unit.
The install process starts immediately after turning on.
It takes about 10 minutes.
When install process is ready, turn off the head unit.
Detach the flashdrive.
Turn on the head unit and it will boot with factory settings like a new device....
Note that there are also ROMs for flashing wit MTC flash tool downloadable.
But the versions for installing from USB sticks ( po russki - dla flashky) are more comfortable to install and I don't own a Windows pc. So this variant was my favorite method...
Regards and good luck...
Edit: if your unRAR program asks for a password for unpacking the RAR file, then use Eazy unRAR app from Playstore on your Android device - it ignores password lock in RAR file ...
Edit2: the 5th gray spoiler in the top header of the Russian forum hosts the links to the ROM RAR files...
Updated to MCU 2.8 - automatic acc off time delay works > 24hours...
I modded the UI2 Launcher a little bit for my personal needs.
See attached screenshot.
(my car, VW golf plus 2013, is now shown in Homescreen...)