Recovery flash won't actually work

[nicari92]

I'm on OxygenOS 5.1.7 (Android 8.1) with unlocked bootloader but stock recovery, coming from full OTA update on rooted OOS 5.1.5, crypted data.
If I try to flash recovery (tried many version, last one is TWRP 3.2.3 siankatabg) from fastboot the flash works with "OKAY" and "Finished" messages, but too quickly (0.013s for writing), and it doesn't actually install TWRP. After reboot I'm still on stock recovery.
I tried to flash full 5.1.7 zip again. It went well, but too quickly, and didn't solve the problem.
How can I fix without having to format data?

 

[strongst]

I'm on OxygenOS 5.1.7 (Android 8.1) with unlocked bootloader but stock recovery, coming from full OTA update on rooted OOS 5.1.5, crypted data.
If I try to flash recovery (tried many version, last one is TWRP 3.2.3 siankatabg) from fastboot the flash works with "OKAY" and "Finished" messages, but too quickly (0.013s for writing), and it doesn't actually install TWRP. After reboot I'm still on stock recovery.
I tried to flash full 5.1.7 zip again. It went well, but too quickly, and didn't solve the problem.
How can I fix without having to format data?

Have you flashed magisk after reboot to twrp recovery? Otherwise oxygenOS will overwrite twrp with stock recovery on its first reboot.

 

[nicari92]

Have you flashed magisk after reboot to twrp recovery? Otherwise oxygenOS will overwrite twrp with stock recovery on its first reboot.

I'm not able to reboot to TWRP! Just after flashing it, if I "fastboot reboot recovery" it reboots to stock recovery

 

[strongst]

I'm not able to reboot to TWRP! Just after flashing it, if I "fastboot reboot recovery" it reboots to stock recovery

Maybe you've missed some steps earlier to the flashing of twrp. Check this guide https://forum.xda-developers.com/oneplus-5/how-to/oneplus-5-unlock-bootloader-flash-twrp-t3624877
If you have further issues, please post a console log of the commands you typed and the errors if there are any.

 

[nicari92]

Maybe you've missed some steps earlier to the flashing of twrp. Check this guide https://forum.xda-developers.com/oneplus-5/how-to/oneplus-5-unlock-bootloader-flash-twrp-t3624877
If you have further issues, please post a console log of the commands you typed and the errors if there are any.

Solved! I was doing "reboot recovery" instead of "boot recovery.img". Noob mistake
Thanks!

 

[BigTurboSkipper]

you need to flash Magisk before rebooting from TWRP

 

[login22]

I am following all the steps in guide but when i try to install TWRP by siankatabg it keeps me looping back to fastboot.
Not facing any issues if i install normal TWRP recovery.

 

[strongst]

I am following all the steps in guide but when i try to install TWRP by siankatabg it keeps me looping back to fastboot.
Not facing any issues if i install normal TWRP recovery.

You should edit your post cause you already solved it by your own.