[Lenovo Yoga Book Guides, News, & Discussion] corvus:
Hi folks.

I'm an Android firmware developer (you can see my posts here in xda) that got a yoga book yesterday. For me it works at it should (by now) but my hacker soul speak to me and said: "at least take a look to see what you can get from this device". I don't have many time, so I can't spend time doing roms or fixing things by myself, but I can share with you some info I get and help you with my knowledge if someone is interested in "play" with this device.

First of all, I'm not responsable of anything that you can break following these steps. Almost all of them are tested and with some common sense you will not break anything, and if you break anything I will try to help you to fix it (if you are polite), but this is a work in progress and hacking and the possibility of brick the device is always there.

I only have the Android version without LTE, so I only tested in my Book.

So, here we go:

1) Secret codes:

I get this codes decompiling EngineeringCode.apk with apktool. Be carefull with them:

####0000# - Display version info

####7599# - Display hardware info

####8375# - Display baseband info

####1111# - Factory test

####2222# - Display SN

####7777# - Factory Reset???

####5993# - Display internal frameWork version

####7642# - Cut the power off to reload the PMIC - This command shutdowns the device. Just press the power button to reboot.

####5236# - Display LCD name

####2834# - ES close test

####8899# - open the ums mode default for debug

####3333# - offline log

####3334# - offline modem log

####9527# - Mediaplayer setting

####78646# - RunIn test

####6020# - switch country code

####59930# - Display current country code

####8746# - Enter engineering mode

####4227# - Enter engineer test

####357# - DLP_TEST

To use these codes, open the contacts app, press the search button and enter the code in the search bar.

2) OTA Images

You can get OTA images directly from lenovo servers. Just open your browser and paste this url:

http://fus.lenovomm.com/firmware/3....WW06_BP_ROW&action=querynewfirmware&locale=en

Change device model if needed (LenovoYB1-X90F or LenovoYB1-X90L)

Change curfirmwarever to a valid OLD firmware, this way you will get the next one in age.

Change locale if needed.

With this url you will get a download url at the end of the result page. In this case: http://tabdl.ota.lenovomm.com/dls/v...S000426_1705080316_WW06_BP_ROW_WC80C2A0F2.zip

These images are not full ota images, they are diff versions. This means that we can't use them to mod the image, or recover a bricked device, but this is a first step :D

3) Custom images

We don't have real sources to build a custom image (the lenovo's open source files are useless), but this doesn't mean that we couldn't modify stock images to take out useless apks or get better performance.

We can get this using an Android Kitchen and a full update image for the device.

As Android kitchen you can use SuperR kitchen (https://xdaforums.com/apps/superr-kitchen/kitchen-superr-s-kitchen-v1-1-50-v2-1-6-t3597434)

As full image, I only tested the one here (https://easy-firmware.com/index.php?a=browse&b=category&id=19521) because I can't download any newer one.

I tested uncompressing it, deodexing the apks and doing a new image. But I don't test it in the device because I need to install twrp to flash the new image and I don't have time to test. But this should work, I did it many times so if someone is interested I can give steps to do it and support for testing.

If someone can get the latest full images, send then to me and maybe I can get some time to do some tests.

PD: Probably we could use this as a base to get LineageOS 14.1 working: https://github.com/latte-dev/android_device_xiaomi_latte/tree/cm-14.1

So, if you are interested in some hacking with the Yoga Book, contact me and we could team to get the most of this device.