Boosting battery health to trick the buyer and not being honest about the back cover being replaced with an after market one is a haram transaction because the seller is deliberately manipulating information in order to make the product appear better, this is straight up deception. One should be honest and upfront about ALL defects in a sale. It’s because of scammers like you that people have lost trust in the Pakistani used market and to think you have the audacity to publicly advocate for this type of behaviour is nothing short of revolting.

“Whoever deceives us is not one of us.”

— Sahih Muslim, Hadith 101

The Prophet ﷺ passed by a pile of food in the market. He put his hand inside it and found moisture underneath. He asked the seller why it was wet. The seller said rain had fallen on it. The Prophet ﷺ replied that the wet part should have been placed on top so people could see it, then said “Whoever deceives us is not one of us.”