Impossible to install Mac OS X

Dear all,

I’m trying to prepare a 2009 MacBook Pro (my first Mac) for a friend who would take it for himself since neither AppleStore nor Brightstar wanted to recycle it.

I followed all steps here https://support.apple.com/it-it/HT201065 even if it can only support El Capitan 10.11.6.

After erasing the disk, I selected reinstall Mac OS X. It duly downloaded it (~40mins), then rebooted once, white screen with grey Apple appeared, charging line as well, “20 minutes remaining” followed then… big X logo of Mac OS X appeared with the writing, paraphrased from Italian:

”impossible to install Mac OS X. No valid package found. Contact your vendor. Exit installation to restart and try again”

I tried again a few times, with no improvement.

Any idea what could have happened and what I may do to solve this?

The Mac worked beautifully until I started following those instructions and tried to reinstall the OS to make it usable for my friend… it would be a pity if, after all these years of service, it would have to end like this.

Any way to bring it back to factory or to make macOS install work?

Thank you