[K3 Note Original Android Development] :
[MENTION=4948627]daniel_hk[/MENTION] sorry that i have not replied. K3 Note only use long Preamble (800ns) (max speed 65mbit). nearly every wifi device i have seen, use short Preamble (400ns)(max speed 72mbit). means that the auto detection doesn't work, because there is no reason to use long Preamble in my setup. i'll would like to help if i could, but my coding experience is nearly 0. but just an idea, you have forced the 5GHz wifi, would it be possible to force the auto detection/short preamble ? the K3 slows down the 802.11N stream from the access point to 65mbit for EVERY user in the network

https://github.com/danielhk/android_kernel_lenovo_aio_otfp/blob/1be06a6a9d8aabca47956b47b118802a0b066d2a/drivers/misc/mediatek/connectivity/conn_soc/drv_wlan/mt_wifi/wlan/common/wlan_lib.c#L1557

i have tried to change this in NVRAM with http://www.needrom.com/download/maui-meta/ or http://www.needrom.com/download/sp-meta-v1-1512-00/, not sure anymore. but basically i have format the K3 Note with SP tool, flashed the full stock rom, and than changed the wifi mac, BT mac, IMEI, turned on 5GHz WiFi, and i have found that i could also change the preamble, default was 800ns, so i guess the auto preamble don't work or it choose 800ns when both types are supported (how stupid is that...) but after setting to 400ns, i still had a long preable and 65mbit max. so my quess is that this change only gets loaded with stock vibe ui rom.

another thing that could be awesome, if the K3 gets support for 40MHz wide channels. with short preable this would give 150Mbit max wifi speed. i know that many OEM disable that, because the 2.4GHz has not so many channels, but since the router/access point decide whether it can broadcast 20MHz or 40MHz wide channels, the client has no impact in that scenario, so even when the phone only support 20MHz (72Mbit) the router still broadcast the 40MHz wide channel.

and a performance trick from me which you could implement in the rom is to disable the ext4 journal file. the journal file is like a middle man before data gets written to the flash storage. like a video buffer (well kind of, you know what i mean). so every data you write on the flash gets written twice, first in the journal file, then on the flash. the use case of this is that if you have for example a power failure, you don't lose the data, because when you reboot, the device "knows" where the data writing was interrupted, and can move on to finalise the data writing. but since a smartphone don't use power from the socket like a PC, a power failure is less likely to happen with a battery (and if the battery is low, the device shutdown so every file writing gets finalized..)

i have disabled this in one of my ROMs, and this has improved the I/O performance. but yeah, you losse some safety as said above ... but in my opinion, worth the trade off because the chance that you actually lose data is wery wery small..

here the link to my ROM http://www.needrom.com/download/play-edition-v2/

you can take a look how i have implemented this in the rom (update-script...) and in the zip itself. don't know if this still works with the latest TWRP, maybe you need to tweak a little bit. i would help if i can.

PS: i don't have the phone anymore, now my sister use the K3 Note, so i can't flash everytime and everyday ^^