[Android General] limited_imagination:
HI PW. I was actually using the volume trick on SP Flash Tool when it failed, but now I think I know why. I had only put just the scatter file in the folder used by SP Flash tool, not the rest of the ROM files. I didn't think I needed it, if all I was doing was reading back partitions from the device. But once I directed SP Flashtool to the folder with the complete ROM, it seemed to work.

After creating that Image.gz-dtb file with the second .config file I attached here in my previous post, fixing the cameras and accelerometers, , I was left with a 7.4 MB file and a lot of dangerous curiosity, like a kid with a butter knife in hand, looking at an electrical socket.

Flashing a kernel is not something I have any experience with, so probably I should have asked for advice about it first, but I just charged ahead.

I used Android Kitchen for Linux v.3.4 and unpacked the boot image that I made from TWRP. It seemed to unpack well, although AK gave me a warning that "Signature with "AVB" type detected."

From there, I went into the split_img folder, found the boot.emmc.win-zImage file, removed that file, swapped my newly compiled Image.gz-dtb into its place in the folder, and renamed it to boot.emmc.win-zImage. I made note that my Image.gz-dtb file was 7.4 MB long, but the boot.emmc.win-zImage file was only 7.0 MB long. Close enough for horseshoes and handgrenades, right? :) They looked similar enough when viewed in a Hex editor that I thought I would give it a go.

Then I used the repackimg script from AK, and it created an unsigned boot image file, called "unsigned-new.img", with the following error:

I renamed the boot image produced this way, to be "boot.emmc.win", as both my TWRP backup and the factory ROM named it.

This repacked and unsigned boot image file was only 9.5 MB in size, but the original boot.emmc.win file produced by TWRP backup was 16.8 MB in size. That was worrying, but when I opened them both in a Hex editor, they looked pretty similar at the start. The TWRP boot image file just had reams and reams of 0000 filler at the end of it, which my modified version did not. By comparison, that factory ROM that I downloaded from the Russian Lenovo forum has a boot-sign.img file of only 8.54 MB.

I decided to try it anyway...

I copied this new (but unsigned) boot image to the TB3-850F.

Initially, I tried to use fastboot to boot this new modified boot image without permanently flashing it to the TB3-850F. From a Linux terminal, I used CD to change into a folder with my modified boot.emmc.win file, and then I used the command "sudo fastboot boot ./boot.emmc.win". I got a message that the file was downloading to the device, and then it booted up fine, but sadly it was still using the original factory kernel.

So I wasn't going to get away with a temporary test. I would have to flash the boot partition.

I used TWRP to do this, through a restoration of a backup folder on the device, where I sneakily first replaced the real TWRP backup of boot.emmc.win with my own modified version of that file.

Once TWRP had "restored" the boot partition, and I restarted the TB3-850F, all hell broke lose, and it started infinite boot looping spastically, about once per second. Only way to turn it off was to hold down all 3 buttons for 10 seconds, then release. I tried multiple button combinations to start it in TWRP, but nothing worked.

Undaunted, I fired up SP Flash Tool (remembering to direct it to the full factory ROM folder and not just the scatter text file this time), and flashed the factory boot image to the TB3-850F.

At that point, the boot looping stopped, but the boot process would freeze indefinitely on the initial "Lenovo" logo. Again, no button press combinations allow me to start up in TWRP. When the device is on, I can't get an adb or fastboot connection to my PC. I need to hold all 3 buttons for 5 seconds to turn it off.

So at the present moment, my TB3-850F ias been reduced to becoming only a rectangular flashlight, with an awkward "off" switch. :)

Next step will be to flash the full factory ROM to the device with SP Flash Tool. You recall that I only flashed the factory boot image with SPFT, but left everything else the same. Maybe it needs the lk and system partitions from that ROM too, in order to work again. Or, maybe it needs everything from that zip file. Hopefully it doesn't need the factory recovery file flashed, because I would like to keep TWRP in that partition.

Should that fail, the step after that will be to remove the screen, and try to swap it onto another TB3-850F that I have here with a broken screen, to get that one up and running.

Should that last option fail, then I guess I'm all out of ideas, and one of you guys will have to carry the baton by yourselves!

---------- Post added at 08:05 PM ---------- Previous post was at 08:04 PM ----------

Are you talking about the source code that I posted on Google Drive?

Did anyone who wanted that, have trouble with getting it?