Yes! it CAN be done.
Send it to Apple and they will change the flash memory size for you too if you want them to.
Here is the hard truth.
2 to 5 years Federal Pen time
Free record for LIFE
Now let us think logically.
If you stood in line for 12 hours for the dang thing, AND it is broken, AND you are too cheap to let an iphone repair shop replace the part for $35.00 (+/-) then definately, go for broke!
I think little out of box, as he owns both serial numbers,he owns both phones,so he is legal owner of both and i think have right to use both phones,even serial numbers as he likes,as he owns it both.He pay for both,other side is is it moral to use it for intended purpose.What if he wants just to transfer serial number of hardware from one same device to other without plans to make fraud,have he right to do that then? For example if i transfer with time part by part from spare device to that one i use it, and with time that one device what is in use have changed so much that deserve to reflect that other serial number,as have most part of it inside or even outside,and that is i think really fair-play,got what i think,now?
Let me say clear,for sake of freedom i think he have right to change serial number from one same device that he owns to other same device that he owns too. Who is owner of both that exact same devices,Apple? or him! He don't rent,he buy ownership of hardware and serial numbers goes with it. Right?
Other story is if he go use or misuse his right. What if he just exchange most or crucial part of interior from one to another ,do he have then right to change ,better to say transfer serials number of hardware from one device to other? As he is legal owner of both. That is question of ownership for me. He owns both hardware,that is fact or not?
So he own both serial number of hardware ,that is fact ,too. Simply as that.
Yes i do not support any sort of fraud,too. Just thinking that he have some rights as owner or hardware.Even software what he buy and legally owns right to use it on one device,i think he have right to erase it from one device and to install to other.
Real question is what we buy? What right we have as owners? What we own? Sure we own hardware and hardware number. That is what i think.