Trying to build 2.6.1 for S21 Ultra

[teneburu]

Hello,

I come here after literally 4 days of trial and error, building again and again (I've hit my 50th iteration, 1 hour per build...), collecting logs again and again... I'm exhausted. I'm really sorry for the following rant, my intention is absolutely not to put pressure on anyone to help me or something. I've seen maintainers ask for patience and not to open issues, but I wanted to share my findings.

I have no android development background, but as I was bootlooping with 2.6.1, I thought "Fine, I'll do it myself, with the help of some AI, I guess updating a build to stop this bootlooping behavior won't be that hard", I was so wrong... but at least I got to learn a bunch of things on the Android operating system.

First, I downloaded and extracted HYH1 firmware from samfw, into out/fw/SM-G998B_AUT and out/fw/SM-S721B_EUX to bypass the latest firmware being pulled by the download scripts, which would make the source firmware of SM-S721B Android 16, while my Samsung S21 Ultra has reached end of support and is stuck on Android 15.
I used the repo as of 2.6.1 release commit.

As expected, if I build with no change to the codebase, and sideload (after a full stock flash of HYH1 and TWRP Odinpack), I get the same bootlooping behavior as with the zip downloaded from the Gofile (I reach Android logo).

I got a bash script to collect device logs, and started digging.
I kept having bad AI answers, followed up by bad prompts as I am not knowledgeable on that field. Android development really seems to be high level dark magic wizardry. I decided to use my own brain and started researching...

My main clue was this message by @majaahh

I wasn't able to see any aforementioned (in issue discussion) "TEEgris blobs" in last_kmsg.txt.
Instead, for me the problem was looking like it was CPEFS partition incompatibility between source and target firmware.
I fixed it by modifying CPEFS mount command in init.baseband.rc with a patch.
So many problems started getting propped up after that, I don't know what to do anymore. It's like a whack-a-mole, every time I try something I mess up something else.

Anyway, I'll stop yapping now, here's a quick list of the problems driving me nuts:

• r11sxxx is used by the "Desixtification" patch (I have no clue what desixtification is about) haven't found a way to make it cleanly use r12sxxx
• VINTF manifest configuration is broken, causing a bunch of "Not found in the VINTF manifest" on system-critical HALs
• VNDK compatibility & apex packages acting up
• system_server process is crashing with SIGSEGV (signal 11) (which is probably the main bootloop reason?)
• abox_tplg.bin firmware file exists in source but may not be properly included in ROM
• vndkcorevariant.libraries.txt is missing, causing linkerconfig failures

If someone is curious and willing to give me some pointers, I would be super grateful. If not it's okay.
[redacted logs zip]

Thank you for coming to my ted talk

[teneburu]

I managed to build for my S21 Ultra!!
Yippie 🥳!!

Turns out all the problems I cited in the previous message are bullshit and probably introduced by me when tweaking around...
And the real problem was that I didn't have the patch binary (I am running Void Linux)... it took a while to figure it out, but by placing a more verbose sed in the unica/patches/signature/customize.sh I came to the realization that the placeholder signature was never applied, which led me to dry-run the patch and find out I am the biggest idiot and ExtremeROM developers did everything correctly. I'm sorry for doubting it, thankfully I kept going back to the original repo state until I found the problem.

For anyone finding this message, here's the step by step:

1. Make sure you are on Ubuntu or that ALL binaries needed for the build are available, unlike my dumb ass
2. Download the latest August patch for your device and for SM-S721B
3. Extract the firmware in out/fw/[your_device_model]_[csc] and out/fw/SM-S721B_[csc]
4. run source ./buildenv.sh [target] and then m

Thank god I didn't create an issue... I'm grateful for this ROM, thanks ExtremeROM developers.

Peace