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S21 FE SM-G990E (Exynos) has screen off deep sleep issue after wifi connection(persist after wifi off).

(Topic created on: 03-05-2024 01:36 PM)

Hello everyone.

My exynos S21 Fe(exynos) has idle battery drain issue when connected wifi. I investigated a bit and found out that phone does not go cpu deep sleep mode when when connected to wifi. Also, this issue persist when connected to wifi once. Only workaround i found restarting phone and not connect wifi even once. Unfortunately phone is not usable without idle drain. I tested idle night drain after restart and only mobile data and phone lost 3-4 percent for 7 hours and it is actually pretty decent for 2 year old phone. I got this unit second hand and don't know previous firmware version has this problem. I tried factory reset, csc change even flashing another region firmware but no avail. This is my xda thread  link:

I shared some screenshots from bbs and gsam tracking programs. Anyone can confirm this behavior? Maybe i have defective unit.

TLDR; Probably exynos variants has idle drain when connected to wifi(persist after disconnection) due to firmware.