I have one reboot in 3-4 dys on FW 20171227. Changed charging board yesterday, old one was v1.1 1728, replaced with v1.1 1737. I'll report about random reboots later. So, after charging board change in January 18, had just one reboot on FW 20171227 in about 2 weeks, but it was not full reboot, just...

I have one reboot in 3-4 dys on FW 20171227.
Changed charging board yesterday, old one was v1.1 1728, replaced with v1.1 1737.
I'll report about random reboots later.

hi. after doing this update and factory reset, i can´t use 4g lte network anymore. imei changed to 11111111111111 in slot 1 and 22222222222222 for slot 2 If you upgraded firmware via FlashTool, it seems you erased NVRAM partition, did you select "Format+Download" instead just "Downlo...

Upgraded firmware to 20171219, cpu successfully goes into deep sleep now

Here is logs from MTKlogger, stock firmware 20171011, just after resetting to defaults

Also, I found some more info in kernel_log, what is absent in normal phones:
[UART]CANNOT GET UART[0] SLEEP ACK

It appears frequently.

Hello! I found some interesting info in kernel_log, hope it will help. It seems CPU tries to go to deep sleep and turn down main PLL, but this step fails and CPU cuntinue working instead waiting for any wake-up signal. Please make attention on this line: <3>[ 457.716288] -(0)[1347:system_server]susp...

Hello! I have the same problem on MT6757CD, phone drains battery, 12-15% per night (6-7 hours, ~2% per hour), CPU does not sleep.
Less than 1 minute of deep sleep in 37 hours in last check.