Hello, first try to check your mic eliminating broken mic problem. You should try default voice recording app on your phone and see if sound quality of recorded voice is in good quality. If it is still in bad quality - you should repair your broken mic. If it is good quality it is not hardware problem. As you can't do factory reset try to scan your phone from malware and remove suspecious apps which you have downloaded. Try malware scanner Malwarebytes.
Hi, @alexniculescu , as many of those series HP computers has GPU chip problems I will sugest you to do short reflow for GPU chip. If you will see any good signs of usage after reflow process then GPU chip should be reballed. Or you can leave it reflowed but for very short usage... Link to youtube video reflow process: https://www.youtube.com/watch?v=dqRRUMSS...
