Hello everyone. I flashed the OpenMode kernel with L2 fix (zImage_2.6.32.54-openmode_l2fix) and install N9QTweak (but didn't enable any tweaks). After this very hard UI freezes appeared. It constantly twitches and blinks (I shot a video https://youtu.be/U8I8GeKf_NE).
I tried to flash the stock firmware again (DFL61_HARMATTAN_40.2012.21-3_PR_LEGACY_001-OEM1-958_ARM, with and without secure zeroing MMC), but freezes didn't disappear (!).
l also tried to flash various MMC images:
UKIRELAND_EMMC_UKIRELAND, EURASIA_EMMC_EURASIA and NOMAPS_EMMC_NOMAPS,
but nothing helped. After each iteration of the firmware flashing, freezes changes: either weaker or stronger. But they don't disappear completely.
Freezes even in the flash firmware mode and during boot. Also in the firmware mode there are artifacts at the bottom of the display:


Maybe this is a hardware problem?

Could be. It also looks to me that the "NOKIA" logo in the screen is skewed, but maybe that is just te angle of view?

Yes, this is the angle of view. The main problem on the video that I shot.

Why dont try to flash with firmware Switzerland maybe fix this problem

Didn't help

I don't think it's a hardware problem - well, thats just an opinion of course.

You can try to re-flash from scratch with the instructions here: https://dt.iki.fi/nokia-n9-resurrect (mostly just additions to the official instructions)

I flasehd in various ways, including the secure erasing mmc option. Nothing helped. On some firmwares, the freezes became smaller, but still they were.

I found the problem in the hardware - the degradation of the SoC or DRAM soldering. I heated the SoC area to 200 celsius degrees and the friezes passed. Need a SoC reballing or replacement.