[Asus Zenfone 5Z  Guides, News, & Discussion] AryanAA:
OSS Vendor Flashing Guide
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Note: This guide is deprecated now, kindly refer to the guide above for latest ROM builds.

So after tons and tons of test builds, the good ol' devs managed to get everything working and gave us a super stable ROMs (many more to follow soon ;) ). However, since our device supports A/B scheme, a newbie can find it rather difficult to get used to flashing ROMs, kernels and even GApps! So I decided to prepare a simple guide which should help you get used to flashing ROMs and lots of other stuff.

Disclaimer: If you don't know what bootloader is and/or don't know anything about Custom ROMs, I strongly recommend you to not try this on your own and rather watch some videos about them and the advantages/disadvantages associated with them.

Notes:

1. Prerequisites:

Unlocked Bootloader

ADB, Fastboot and Device Drivers (Google them)

Use Command Prompt instead of PowerShell for ease of use.

STEPS:

1. Boot into Fastboot mode (power+vol up) and run:

fastboot -w

Note your active slot from here. Mine is 'b' as can be seen from the pic attached. Yours can be 'a' or 'b'.

View attachment 4785824

2. Download vbmeta from View attachment 4961371 and then do this:

fastboot --disable-verity --disable-verification flash vbmeta vbmeta.img

3. Now run the following command in your fastboot using pc(obviously):

If your active slot was 'a':

fastboot set_active b

If your active slot was 'b':

fastboot set_active a

4. Either restart bootloader directly from your phone (using volume and power keys) or do this:

fastboot reboot bootloader

Your fastboot screen should now look like the following. Notice the change in the active slot (if yours was 'a' in the previous step, it should be 'b' now).

View attachment 4785825

5. It's TWRP time!!

Download TWRP (both boot.img and permanent zip) by Jackeagle from here.

Flash TWRP using:

fastboot flash boot boot.img

Make sure the name of your downloaded twrp image file is boot.img! If not, either rename the file or change the fastboot code to that filename.img

6. Now reboot to recovery using power and vol keys on your phone. You should see TWRP booting up now. If not, you've messed up somewhere, do the entire process again (correctly ;) ).

7. Click on WIPE > ADVANCED WIPE, and choose System, Dalvik (Cache) and Data.

8. Flash OSS Vendor. You can flash via fastboot by downloading and extracting OSS_Fastboot.7z. Navigate cmd to OSS folder and run:

fastboot flash vendor vendor.img

Alternatively, you can simply flash OSS_Recovery.zip in TWRP/SHRP.

9. Now, if you unlocked your bootloader via official apk (provided by Asus), then flash ABL.zip in TWRP/SHRP. However, if you unlocked unofficially, you can skip this step.

10. Now, flash permanent twrp from here, change to the inactive slot and reboot to recovery again. Flash the same vendor you flashed on the other slot. In other words, repeat Step 8 (no need to flash abl again).

11. Time to flash the ROM of your choice. :D ! Click on INSTALL and then choose the ROM you want to flash. SWIPE>>>>>>>>> :p

12. Flash TWRP permanently using this: Permanent TWRP. Flash this simply in twrp.

Note (optional): Mount vendor before performing this step just to be safe.

13. Reboot to Recovery (IMPORTANT)

14. After rebooting, twrp would have automatically switched to your active slot (the one you had in Step 1)(check this in reboot section of twrp).

15. Now you can flash GApps, Magisk from the active slot anytime. This step varies from ROM to ROM as some ROMs have GApps pre-installed.

Note: Access TWRP by pressing power+vol down button simultaneously.

16. REBOOT>SYSTEM and you're done! Enjoy the ROM. 👼

Credit Section:

1. Jackeagle -- TWRP and ROM Developer

2. Rohan Purohit -- ROM Developer

3. Sandeep.Sethi -- Kernel Developer

4. All the testers.

Thank you and I hope this guide benefits the community.