I do not know where it is more profitable to sell such devices in your country. You can try it on the marketplace. I know they are well bought on eBay

Yes, you can easily sell it Such devices are well bought by repairmen for spare parts

That's what I was thinking. error 4013 is caused by a problem with the NAND chip. This chip is the storage in your device. this is a common problem and spontaneous reboots are a symptom of it. This is solved by soldering a new chip. you need to contact a specialist or exchange the phone under warranty

what was the error code?

It looks like you are incorrectly flashing your device through iTunes. When restoring, did iTunes give you any error numbers? for example 4013