Sometimes we feel confident in our soldering skills (but only sometimes) — and then we see something like this done.
Someone over on the XDA developers forum managed to upgrade his Nexus 5 from 16gb to 64gb — and not only that, upgraded the eMMC type from 4.5 to 5.0 so it writes and reads much faster.
While the details on the actual conversion are a bit vague, we did manage to dig up another video of someone replacing an eMMC chip from a Samsung Note 2.
It most certainly is possible… but would you look at the size of that chip!
