[Honor 9  Guides, News, & Discussion] oslo83:
Here is a list of hidden settings & tweaks for EMUI8.0 .

They were tested on oreo STF-L09C432B360 but should work on others EMUI8.0 devices.

Other version than European C432 should switch "/eu/" part in original filename with region codename of their firmware.

Root access is needed to be able to edit these file ; Keep files' permissions & owner's rights as they were.

For rooting EMUI8.0, I'll suggest magisk 15.4 until a better solution appears.

Show 4G/LTE switch in network settings

In :

/cust/hw/eu/prop/local.prop

Look for :

ro.config.hw_hide_lte=true

Edit it to :

ro.config.hw_hide_lte=false

Reboot

Show 4G/LTE switch in quick settings

In :

/cust/hw/eu/xml/hw_default.xml

Look for :

<integer settings.global.hw_4g_show="0" reset="true"/>

Edit it to :

<integer settings.global.hw_4g_show="1" reset="true"/>

Reboot

Change icons' title fontsize

In :

/product/etc/xml/hw_launcher_default_config.xml

Look for :

<item name="config_IconTitleSize">12</item>

Edit with the number of your choice beetween ? & ? :

<item name="config_IconTitleSize">10</item>

Reboot

Show icons' titles on 2 lines

In :

/cust/hw/eu/xml/hw_default.xml

Look for :

<string app_name_two_lines="false"/>

Edit it to :

<string app_name_two_lines="true"/>

Reboot

Huawei Call Recorder

Follow this link

Huawei Face Unlock

Follow this link

Testing in progress :

Add '4G/LTE only' mode to prefered carrier modes list in network settings

In :

/cust/hw/eu/xml/hw_default.xml

Look for :

<string hw_add_4g_only="250"/>

Change or add your carrier's mcc number.

Note : [adding mcc numbers with ';' or ',' ?] [need testing with 'all' , '-1' , 'ALL' or nothing for mcc parameter)

Testing in progress :

Replace '4G' by '4,5G' in both settings and status bar

In :

/cust/hw/eu/xml/hw_default.xml

Look for :

<string hw_show_4_5G_for_mcc="286"/>

Change or add your carrier's mcc number.

Note : [adding mcc numbers with ';' or ',' ?] [need testing with 'all' , '-1' , 'ALL' or nothing for mcc parameter)

Testing in progress :

Add 6x5, 5x6, 6x4 & 4x6 icons layout to homescreen settings

In :

/product/etc/xml/hw_launcher_default_config.xml

Look for :

<item name="config_desktopCellsOptionItems" reset="true">4x5,4x4,5x4,5x5</item>

-WIP-

Layout 6x6 not working

Testing in progress :

Change begin date of monthly data usage cycle

In :

/data/user_de/0/com.huawei.systemmanager/databases/netassistant.db

With a sqlite editor change this value :

settinginfo / begin_date

Change it from null to the day's number your monthly data plan starts.

After editing : Double check UID & GID ownerships are still set to 1000 (system).

Show 4G+/CA switch in settings

In :

/version/special_cust/STF-L09/hw/eu/prop/local.prop

Look for :

ro.config.support_ca=false

Edit it to :

ro.config.support_ca=true

Reboot

Show data roaming options in settings (options available are: disabled/domestic/international)

In :

/cust/hw/eu/xml/hw_default.xml

Look for :

<string hw_data_roam_option="26006,27211"/>

Change or add your carrier's mcc&mnc number.

Note : [need testing with 'all' , '-1' , 'ALL' or nothing for mcc parameter)

Reboot

Wifi bridge enabler

Follow this link

PS: I use TotalCommander on android but others files explorer with root access should work too.

MAKE BACKUPS BEFORE YOU EDIT ANY FILES !!!

0. Check file's permission & file's owner and remember it.

1. First backup the original file in a backup directory.

2. Copy again the original file in a custom directory with user's rights.

3. Edit file on this custom folder.

4. Delete original file on original location, then hurry to step 5.

5. Copy previously edited file from custom folder to original location and accept when TotalCommander ask about re-mounting partition.

6. Verify file's permission & file's owner in original location.

I'll update this OP with new tweaks & settings as they are uncovered.

Reasons for editing:

-typos, visual work-over, added file's ownership (UID) infos

-added 'Change begin date of monthly data usage cycle'

-added Wifi bridge, CA settings (4G+) & Roaming options