These are more complex backup steps. Its useful if you want to do beyond a Simple System Backup which is good enough to recovery from bricking but do not save user installed apps and data.
This is the most complete backup for recovery. HU's complete flash memory storage (EMMC) is saved. it is quite a bit more complex than the saved items above and also require more time and storage resources. For 128GB HUs here are example requirements
Takes almost an hour and battery needs to be kept charged (and any car auto shutoff if accessory mode avoided (my 2011 Prius does)). See here. Smaller flash HU such as 32GB is about 15min.
Require sufficient storage on PC to fully copy HU EMMC ( 2x HU's flash memory size of 16GB to 128GB ). This might be challenging if don't have a better PC available.
NOTE this doesn't save IMEI so need to also save that.
Read here
TWRP replaces your recovery and will be overwritten after each (OTA) update. TWRP needs to be flashed via PC first. Even if you could copy backuped files to PC afterwards, you'll need a working TWRP for a full recover. If your HU is bricked, this might be impossible and hard to recover (we have no experience so far). Therefore TWRP backup is only recommended if you know what you're doing and you are a big TWRP fan. 😄 See here.
Windows 7, 8.1 , 10 or 11 to run flashing software. Linux may also work, but has not been tested.
SIM tray tool or paperclip for triggering "RST" (reset).
USB cable with USB-A male end to HU and the other end to the PC (USB-A or USB-C). Some older thread says <= 1m. I used ~2m and very old (from USB 1&2 era) and worked fine. Someone needed to use a Y cable to have enough power for flashing (see here at XDA). I guess this maybe PC USB port power level dependent. Most people seem to not encounter this problem.
SP Flash Tool 5 (Important: version 5, not version 6)
MTK Driver. Install the driver with admin privilege (not sure if necessary). Installation may ask if want to remove USB drivers. Click "Okay" (it's only removing previously installed Flash Tool drivers, doesn't touch any other USB drivers). Let it finish and reboot Windows. I had to prompt the installation with return key a couple of times to get it to finish.
Only for Windows 7 and 8.1: If installation of driver fails when connecting HU to PC, uninstall MTK Driver, install archived version 5.1632 and reboot Windows.
For advanced users only: Logo comparison and dump tool (GitHub repository). Towards the bottom of README file have the example use. README can be displayed in plain or md formatted output. Be sure to click Code option (upper left) to view without md formatting.
Although backup with TWRP is also possible, the way via SP Flash Tool and WwR MTK is recommended. One reason is, that you don't have to modify your HU to make a backup (with TWRP you'll have to flash TWRP first) and another is that there are no requirements for recovery (e.g. an installed and working TWRP (TWRP will be replaced after each OTA update by the default recovery)). Also a wrong display driver could prevent you from recovering a TWRP backup.
You should be able to fix every soft brick like wrong display driver with this way of backup (hard bricks like wrong preloader flashed won't be solved of course) as long as you have an intact backup available.
Before flashing anything via PC you should always make a backup of your working firmware in case of problems like wrong display driver.
It's the same as described at Flash firmware (1.73.8+/1.80.1+ upgrade or brick recovery) via PC, but instead of using a downloaded firmware use your assembled firmware made with WwK MTK ("Cut the ROM including userdata") from chapter above and select their scatter file. If SP Flash Tool also here complains that the CPU is not supported, open the scatter file and change "platform" from MT8259 into MT6761 and load the scatter file again.
After recovery and booting up, Android complains about missing IMEI. Just follow #18 of flashing tutorial.
Here is a good tutorial how to backup (please read at least the first 2 notes below):
Here are a few notes for the video:
You need twice the amount of size of your HUs internal storage as free space on your PC storage (e.g. when your HU has 64GB internal flash storage, you need at least 128GB free storage on our PC; this is needed because there are 2 steps and and also the free space of the HU will be saved in backup; the good thing is, you can compress the files afterwards and the files of each step should be smaller than the used internal space of your HU, but requires temporary even more free space).
You need to save your IMEI before, because it can't be recovered with the backup. Although it doesn't seem to be necessary, it's highly recommended to also safe other things like metazone.bin, 360 camera calibration data and app activation codes.
Timestamp 4:00: Since the CPU is not listed, add a new one called "MT8259". If SP Flash Tool later complains that the CPU is not supported, open the created file and change "platform" from MT8259 into MT6761 and load the scatter file again.
Timestamp 6:50: Partition size/length of BOOT1 can be also "0x40000" (you can verify it with AC8257_Android_scatter.txt file of your downloaded firmware, it's the partition size of preloader partition and should be in line 26), but you can also use "0x80000", it shouldn't matter, since everything behind 0x40000 is empty. After Readback of BOOT1 with SP Flash Tool you can extract the preloader with WwR MTK. I think this is always a very very good option to have a backup of original preloader. It should be about 208kb in size.
Timestamp 11:30: If you want a full backup, take the start value of "sgpt" (last row), open Windows Calculator, switch to programmer mode and HEX on left side and paste the start value of "sgpt" (last row) and add the length value of "sgpt". The result is the size of all partitions together.
See also here: https://www.hovatek.com/forum/thread-22701.html
Another way to get whole user partition size, you can use SP Flash Tool and start "DRAM Flip Test" in "Memory Test" tab for a few seconds. On the left hand side click on EMMC Flash, scroll down and you'll see "UA Size" which is the value you want. It should be the same size as the result described for timestamp 11:30.
Best is to go both ways and if the results are the same, you should be on the safe side.
Timestamp 12:30: For full backup you have to enter the length of the whole user partition you got before of course.
Timestamp 13:00: Depending on your flash size, readback for user partition will take some time, because it also dumps the free space (for a 128GB HU it took almost 50 minutes)!
I highly recommend to keep the dumped user partition, because you can redo the next steps in WwR MTK and vary them in case of something goes wrong. You can compress the file into ZIP, RAR, 7Z or whatever for saving the also dumped free space.
Timestamp 18:20: In the line starting with "The ROM contains GPT scheme, ..." both hex values ("should be" and "has the following size") must be the same for a full dump.
Timestamp 18:50: Depending on your used storage size and speed of your PC drive, assembling the firmware also can take very long.
You can open the dumped firmware ("EMMC_USER" file) and the assembled firmware ("Cut ROM as it is" files) with 7Zip, test the files and also extract single files.
Its possible the extracted logo.bin is not in the repository. This could help others in the future. Read here
Source: https://xdaforums.com/t/ac8259-cpu-based-hu-problems-questions-mainly-yt5760.4171219/post-89671638
If you are familiar with UNIX/Linux/macOS shells (or willing to follow fairly simple command line process), tools are available to dump logo file info and compare against existing display drivers. See Tools needed for backup ("for advanced users only"). Basic Windows tools are also in development.
Video of dump tool in action using a free online Linux VM:
Video of compare tool in action using free online Linux VM: This is useful for people who wish to know which xyauto display driver is same as their HU's logo partition. This could benefit the larger owner community to gain statistics on which display drivers are most prevalent.
Comparing all the display drivers takes 15min. Forward to the end to see the match found. 😉
Currently, the dump tool only provide:
Pixel dimension ( X and Y seems inconsistent )
Interface (LVDS or MIPI; not always displayed in System Info so this may provide more knowledge)
Logo image. Can easily tell orientation by visual inspection.
The comparison tool will compare
The first ~24KB of logo file which include panel set parameters and can be considered as a signature of the display driver.
Does not compare the logo image (could change on extracted logo if changed boot logo image).
Can compare the extracted logo file against a directory full of display drivers (.tar.gz files) in MEGA repository. This comparison may yield more info from the display driver file name which may show panel model.
A few notes for command line / ~UNIX shell newbies:
The 2 tools must be stripped of the .txt extension post download. This is more than just edit the file name and delete the .txt extension. Need to find file properties in your PC OS and deleted it properly there.
Even missing 1 character in the command can fail and mess up whatever. When in doubt, just erase the intermediate files and restart. If using the free online Linux VM noted in the link. Just close the browser window and restart again.
If you choose to do this exploration. Please make a summary post at XDA similar to this post:
https://xdaforums.com/t/ac8259-cpu-based-hu-problems-questions-mainly-yt5760.4171219/post-89783156
Your logo.bin file could be a new one that is not in the repository. This maybe quite valuable to other HU owners if they brick their display. Forward the following to me if your comparison doesn't find any matching display driver. Please provide the following:
logo.bin
System Info screen
LCD panel model if you have it (requires full disassembly, so ok if don't have it)
HU model ID if known
Seller website/link if known
Flash TWRP and launch it.
Choose "Backup".
Select all partitions.
"Select Storage" to USB stick.
Enable compression.
Swipe to backup and wait until it's finished. It takes about ~4GB for base HU Android system + your user data files in addition. Note: Backup says it doesn't backup pictures and downloads.
Source: https://xdaforums.com/t/ac8259-cpu-based-hu-problems-questions-mainly-yt5760.4171219/post-88206725