Can I swap logicboard or HDD from one iPhone 6 to another

"Not that easy.

You'd have to use special tools to rewrite flash memory to change the serial number, then DFU and restore iOS on the grafted device.

The device enters DFU mode if you replace the main flash memory, and Apple activation servers will refuse to activate this device because the device S/N mismatches with the IMEI written into the baseband. So low level reprogramming is required."

Yes you can ive done many aslong as its the iphone 6 with both phones as all you do is YouTube it and make sure you follow the screws probably as one wrong screw with mess you phone up but I changed a motherboard from a smashed up iphone 6 I bought and checked it was all clean then I replaced it with the logicboard from the smashed up iphone 6 and its what im using now and please remember the memorie of the new logicboard gos to the one your putting in and everything on it and if your no comfortable doing it get a professional to do for you as you will have a new iPhone working as mine was iCloud locked thats why I bought the smashed up one just for the logicboard so good luck

The problem is this your question has a two part answer yes you can change the nand flash memory on a logic board. you can also switch it BUT in order to activate the phone sadly you must wipe the nand disk n reprogram it to the S/N of the device so like the gentleman above stated you need serious microsoldering know-how and how-to proper handle this extremely delicate tiny chip to properly complete this task. this is because apple servers are trying to prevent counterfit phones from being activated by there servers. your phone would not be counterfit BUT because of apple servers having this feature your new phone would fall into this catagory thus forcing the phone into DFU recovery mode upon boot and DFU mode requires the phone the have a full restore to factory settings with all memory and data erased.. Sorry Geremy C i know how it is to have your life inside a phone and i totally feel for you :( Try Wondershares Dr Phone toolkit.. it has a recovery feature for broken phones that may be helpful im not sure if u need to be able to power it on or not but give it a look. hope this helps.

can i change my iphone 6s plus board into iphone 6 plus

can I swap logic board iPhone 6 with iphone6s.

ok so from my understanding ive read 2 different answers here, my question is, I have an iphone, perfect condition, fell, then stopped working after a week. It shows the battery and charging port are well but it wont turn on, so they told me its more than likely the motherboard (logic board) i have a lot of things (memories, photos, videos, apps, music, etc) stored on that phone that i really really dont want to lose, if i can get an iphone 6 with a smaller memory (i.e. buy a 16 gb iphone 6) can i swap my memory/storage (128 gb iphone 6) onto that motherboard, or is my stuff pretty much lost forever?