[Android Software Development] patrikson:
I should have mention it, that I figured out why you used fork, for other interested: LoS 17.1 is not even an option with original source code.

Once I built docker image from that fork I hadn't had any issues with automatic downloading TheMuppets code for chiron device.

EDIT3

As a metter of fact, I do have those 524 errors, I didn't notice them earlier. So I had to clone this repo manually as well.

I wish I had your reply earlier it took me a while to figure out things, but on the other hand I had a chance to learn new things ;)

Now my docker crashes with this error:

>> [Tue Jun 16 05:51:46 UTC 2020] Missing "vendor/lineage", aborting

I have to figure out what's causing it. EDIT: I guess something went wrong during download, I did clean build of docker image and pruned volumes and downloaded data, and build is running.

The links from above look promising, but I won't mess up with my actual environment, if I fail, then I'll retry with new sources.

EDIT2:

Build failed:

repo sync has finished successfully.
Device chiron not found. Attempting to retrieve device repository from LineageOS Github (http://github.com/LineageOS).
Found repository: android_device_xiaomi_chiron
Default revision: lineage-17.1
Checking branch info
Checking if device/xiaomi/chiron is fetched from android_device_xiaomi_chiron
Adding dependency: LineageOS/android_device_xiaomi_chiron -> device/xiaomi/chiron
Using default branch for android_device_xiaomi_chiron
Syncing repository to retrieve project.
Repository synced!
Looking for dependencies in device/xiaomi/chiron
Adding dependencies to manifest
Checking if device/xiaomi/msm8998-common is fetched from android_device_xiaomi_msm8998-common
Adding dependency: LineageOS/android_device_xiaomi_msm8998-common -> device/xiaomi/msm8998-common
Using default branch for android_device_xiaomi_msm8998-common
Syncing dependencies
Looking for dependencies in device/xiaomi/msm8998-common
Adding dependencies to manifest
Checking if kernel/xiaomi/msm8998 is fetched from android_kernel_xiaomi_msm8998
Adding dependency: LineageOS/android_kernel_xiaomi_msm8998 -> kernel/xiaomi/msm8998
Using default branch for android_kernel_xiaomi_msm8998
Syncing dependencies
Looking for dependencies in kernel/xiaomi/msm8998
kernel/xiaomi/msm8998 has no additional dependencies.
Done
07:44:26 Build sandboxing disabled due to nsjail error.
ESC[1mframeworks/native/build/phone-xhdpi-4096-dalvik-heap.mk:19: ESC[31merror: ESC[0mESC[1m_nic.PRODUCTS.[[device/xiaomi/chiron/lineage_chiron.mk]]: "vendor/xiaomi/msm8998-common/msm8998-common-vendor.mk" does not exist.ESC[0m
07:44:27 dumpvars failed with: exit status 1
07:44:28 Build sandboxing disabled due to nsjail error.
ESC[1mframeworks/native/build/phone-xhdpi-4096-dalvik-heap.mk:19: ESC[31merror: ESC[0mESC[1m_nic.PRODUCTS.[[device/xiaomi/chiron/lineage_chiron.mk]]: "vendor/xiaomi/msm8998-common/msm8998-common-vendor.mk" does not exist.ESC[0m
07:44:28 dumpvars failed with: exit status 1

** Don't have a product spec for: 'lineage_chiron'
** Do you have the right repo manifest?

No such item in brunch menu. Try 'breakfast'
>> [Tue Jun 16 07:44:28 UTC 2020] Failed build for chiron
>> [Tue Jun 16 07:44:28 UTC 2020] Finishing build for chiron
>> [Tue Jun 16 07:44:28 UTC 2020] Cleaning source dir for device chiron
07:44:29 Entire build directory removed.

#### build completed successfully (1 seconds) ####

~

Any ideas how to solve it?

FINAL EDIT

The error above was raised by my lack of knowledge...

For anyone facing same issue - when you clone the repo to earlier mentioned directory, keep in mind that you have to rename (mv) .git directory to proprietary_vendor_xiaomi.git . It took me hours to figure out... :P