Here is the full stable Marshmallow firmware C636B510 for Honor 4X Che2. This update is available via OTA as well for manual download and update. The build has brought much stability and bugs fixing plus performance improvement. If you willing to Update Honor 4X Che2 L11 to B510 Marshmallow manually then here is the official link as well concise guide.

DISCLAIMER: Only Update Honor 4X Che2 L11running B330 Lollipop to B510 Marshmallow via this guide. Never use for any other variant. Although it’s an official and stable firmware however, use the guidelines only at your own risk.

Firmware Info:

Device- Model: Huawei Honor 4X [Che2-L11].
Firmware: EMUI: 4.0 [Android 6.0 Marshmallow].
Firmware Build: B510 – Che2-L11C636B510.
Region: Asia Pacific.
CUST Number – Code: CUSTC636D001- 05012WRS.
Status – Type: Official (stable) [Full firmware].

Preps| Downloads:

Backup for important data on Honor 4X is recommended.
Sufficiently charge the Honor 4X battery before flashing.
Install the latest USB driver or Hi-Suite at the PC for smooth connectivity. [Download Here].
Honor 4X should be running on B330 Lollipop firmware.
Also, Honor 4X should have stock recovery and not rooted.

Download B510 firmware zip file for Honor 4X Che2. [Official Link] – [Size: 1.40 GB].

File: [Che2-L11_C636B510_Firmware-Bangladesh-Viet-Nam-Cambodia-Lao-People’s-Democratic-Republic-Nepal-Sri-Lanka-andriod-6.0-EMUI4.0-05012WRS.zip].

Steps to Update Honor 4X Che2 L11 to B510 EMUI 4.0 Marshmallow.

Download B510 Marshmallow .zip from the link above and then unzip.
Now search and copy dload folder from the unzipped firmware contents at the root folder of micro sd card.
Disconnect Honor 4x safely and then turn off.
Now hold pressed the Vol-Up+ Vol-DOWN+ POWER at the same time for a few seconds.
The force updates process triggers auto.
Wait until Honor 4X normal reboot.