Hi leonardoblassl,
We would suggest you check:
https://www.asus.com/support/FAQ/1009748
During the update process, please charge your phone with the AC adaptor or make sure the phone has at least 15% battery life available.
Is there any error message?
Could you show us a screenshot or short video of the problem?
To share videos, please upload it to ASUS WebStorage (https://www.asuswebstorage.com/navigate/) and share the link with us.
Kindly tell us how you installed step by step, and in which step the error occurred.
Thank you
🙂