Recovery mode doesn't work

Question

I've followed these steps to try to root my phone. Then, I continue following this guide but I'm stuck where it says "Paso 2":

I'm trying to access the recovery mode in my PC with the adb reboot recovery command but my smartphone shows the "No command" message and icon on the screen and after I while, it just restart normally.

I just wanted to install Magisk so I did.

C:\adb>adb reboot-bootloader

C:\adb>fastboot flash recovery recovery.img
target reported max download size of 536870912 bytes
sending 'recovery' (21104 KB)...
OKAY [ 0.491s]
writing 'recovery'...
OKAY [ 0.235s]
finished. total time: 0.736s
C:\adb>fastboot reboot
rebooting...

finished. total time: 0.010s

and then I was expecting to be able to enter the recovery mode, but I've tried all the possible key combinations and I can

Actually, before the "No command" screen I get a warning message asking me to visit: g.co/ABH saying that "your device software cannot be checked for corruption. Lock the bootloader. PRESS THE KEY POWER TO PAUSE BOOT. Your device will boot up automatically after a while" and it just restarts normally

I also found this file: /system/recovery-from-boot.p I've read this is preventing me from entering in the recovery mode, but as I'm not root, I can't find a way to delete it or rename it...any suggestion, please?

More info about my phone:

Also, my goal is to install Magisk, so if there is any other way to do it, it will be welcome too.

Answer 1

When you are in fastboot mode you can directly start the recovery image without installing it:

fastboot boot recovery.img

Alternatively if you want to start the installed recovery rom execute

fastboot flash recovery recovery.img    
fastboot reboot bootloader

and then select Recovery using Vol-Up/Down buttons + Power button to start the recovery ROM.

Note that some stock firmware images will replace the recovery ROM back to the original one once you start the main OS. This is automatic "updating of the recovery ROM" is part of the boot process.