I updated software on my Note 4 about a week ago (end of January 2017). On Friday night, my phone went into a boot loop, out of nowhere. I purchased on my phone about 8 months ago from Amazon as a certified refurbished phone, using Amazon as the seller. I've had few issues with this phone, but the one big one is that it dies at ~10% battery. Even with other Note 4 batteries (also purchased from Amazon, using Amazon as the seller) have had this issue. I kinda just live with it now.
Anyways, when the boot loop first started, my battery was at 20% and I'd just turned on my flashlight app. It turned off by itself (battery sometimes also occasionally will ramp down in % quite rapidly below ~18%), and I could feel the vibration/haptic motor vibrate on/off about once every 1-2seconds. So I put my phone in charge and woke up with a full battery (phone off, but display showing the green battery at 100%, and the indicator LED showing green, too).
At this point, I turned on my phone, and the boot loop started. I first wiped the cache partition, knowing this had worked before, after an update. No luck.
After that, I decided that most of the relevant data from my phone was on my SD card, aside from contacts, so I pulled the trigger on wiping it with a factory reset. Again, no luck... still boot loop! So, I wiped the cache partition clean again and did another factory reset. ...Still in a boot loop.
I looked up how to re-install the old factory firmware and downloaded Odin and the original firmware for the Verizon model (I have SM-N910V). Odin recognized a device plugged in and accepted the md5 file that I loaded to it, but there was never a handshake between Odin and my phone. For some reason, it wasn't being copied.
Now, I figured maybe Kies or Smartswitch could help. First of all, I'm 95% sure Kies3 is the correct version, but I'll go ahead and inform you that I downloaded Kies 2.6 and Smartswitch as well. Every single version of Kies and Smartswitch says the device is not supported and to look up the software which my device is compatible with. lol ok bro.
Anyways, in Kies3, I tried to use Tools > Firmware Upgrade and Initialization. After entering the model, SM-N910V, Kies asks for a serial. I enter in the IMEI number located on my phone, but it says the serial is incorrect. The IMEI is the only relevant number that I can find since Samsung didn't add a S/N line to the label beneath the battery. I've read other posts that say Samsung plays a game of he-said-she-said with Verizon/AT&T/Sprint/T-Mobile customers where allegedly the carrier has the S/N of your phone, but then when you try to get this number and [carrier] says that Samsung is the one that has it.
I should note, too, that the phone becomes incredibly hot during the boot loop. Like maybe even hot enough to cook eggs (not exaggerating). I know it's been speculated that the boot loop is caused by overheating, but I'm almost certain that the software wouldn't send it into a boot loop, since that causes it get waaaay hotter.
I've also tried using my other battery, too, but the boot loop does not seem to be affected by that.
Also, when the battery is left in the phone, the phone begins the boot loop by itself without me having powered it on. I physically have to remove the battery from the phone in order to turn it off.
It should be noted that I CAN access the Recovery Menu (Home, Power, Volume Up) and I CAN access the rootloader menu (Home, Power, Volume Down). The rootloader menu seems almost pointless since Odin and the phone don't make a full handshake, though.
At this point, I am allowing my phone to discharge my good battery in hopes of being able to charge it up without turning on. Any advice on how to fix this boot loop would be much appreciated. Thanks!