I tried unlocking this tab years ago and faced the dreaded "Unknown Error" and so I just gave up and never touched the software of this tab. Infact, this tab was the only virgin device i have ever had in my posession till now haha. I just read this post, booted up the tab with its 3 year old used rom, downloaded and installed the unlock tool and tried again. I had the account password error, so I just removed my gmail account and tried again - and it successfully rebooted and unlocked itself. Literally unlocked in 10 minutes. HOLYY ****TTTTTTTTT THANK YOU ASUS! Now to find a custom rom that cure this lag!
Edit : Maybe forward this info to news team? This could bring life to all the refurb Transformers that were locked out and thereby laggy and worthless.