[Galaxy Note 4 General] samep:
All I'm convinced of is that Samsung has this information and Samsung doesn't want to talk about it. This is long out of warranty.

I had Samsung lower level support on the phone one day, the guy admitted that he was new to Samsung, but came from a well known corporation as an IT specialist. Be dug through some notes but wasn't forthcoming in the contents. The many questions I had, he said advanced support should answer. He placed me on hold but the call was never picked up nor was there a confirmation that my call was forwarded to any where. I waited 45 minutes and gave up thinking Samsung didn't want to disclose the info and likely chastised their new employee for suggesting there may be answers to my inquiry.

The initial support guy only confirmed that there was an ongoing eMMC failure that was noted as an update issue. He agreed it pertained to both OTA and Odin or Smart Switch. That is, in his opinion, he was inclined to agree with that theory. I've always felt it was suspicions like poor battery health or defective battery and heat that updates task the phone with that contributed to this issue. But if there is more to it, only the update notes or ongoing update issue can confirm that. I don't know if those are still available but I recall seeing them on the web somewhere. The verbal confirmation from lower level support only gives a little support to the theories. I don't claim them to be fact, just theory and Samsung knows but doesn't share that.

I emailed concerning this call and no joy in connection but emailing Samsung will often result in an no reply mailbox message sent. You cannot just reply back and say you didn't answer the question. Evasive corporation but to be fair, the warranty is up, Samsung only wants to discuss profitable business. Fix your phone? They're listening and responding. Will you fix my phone if it breaks? Don't care to respond. How often has this failed? Silence. Do I get a discount or complimentary repair for eMMC failure? YMMV. LOL; read the thread. $70 on quick return is an alternative I think is fair.

Samsung actually did reply in kind when an official OTA update on TV broke my TVs volume control. My TV was out of warranty but they were aware the update was causing issues and helped.

IMO, flashing updates in the form of stock tar may be riskier than flashing ROMs. But the stock tar is sometimes required. It may be totally necessary to flash the whole tar for a particular recommended update like changing Android OS version when no TWRP backup exists (the recommended method for that is restore backup and Odin the matching bootloader aka firmware in the bootloader and modem thread). You may get by installing the custom ROM cleanly but you're at your own risk when deviating from OP install instructions. Ported ROMs may be best to follow the instructions as given. Others have posted that they had no consequence being on a different Marshmallow update when flashing the custom ported ROM. That may give confirmation you may benefit without being on the same update to avoid Odin stock tar altogether or even a Odin flash to restore TWRP recovery. But I'm thinking the full tar update might actually be more risky than flashing custom recovery or flashing custom ROMs, kernels or mods in recovery. Just my opinion though.

TWRP has dBm option in settings to use the rm method to wipe as opposed to reformat (I think that's the alternative?) It's been suggested that using that TWRP setting may prolong the eMMC life for rooted users that flash a lot. I'm also not a fan of the suggested multiple 3x wipe of everything in TWRP wipe to include factory reset, format data, advanced wipe all the partitions except ext sdcard. Overkill. And asking for trouble has been suggested as reasons eMMC may wear prematurely. The added extra wipes and reformats and combined with flashing multiple ROMs daily or weekly may wear the eMMC to early failure. But that is another theory in itself.

I don't plan to keep mine much longer because it's a Sprint CDMA version but long live the Note 4; if the bootloader is unlocked, it's a treasure to have. And the repair isn't so costly. I wish the design was revisited complete with updated overkill specs, removable battery, expandable memory, andunlocked bootloader (or unlock support for bootloader since Google wants it shipped locked).

It's a shame no OEM wants to revisit this throwback design with modern specs. I think it would sell! LG might sell more of these if they squashed their death by sudden unexpected and continual reboot issue and offered bootloader unlock support that didn't have to be hacked and only worked for T-Mobile models. Just saying... LG V models don't really count as a Note 4 throwback. Get it right, LG.

I've rambled long enough on the subject. I hope you're happy with your purchase and it lasts. I say it's worth the investment of buying extra accessories. I've found Pen useful; the phone can warn you if you walk too far away from a misplaced pen. I've never lost mine for that reason. The tip hasn't worn out either but I don't use it a whole lot either. Personally, I'd focus on case and battery for extras and backup USB cable and get a standard charger for backup rather than fast charger. Slow charging will likely increase battery life and not fall too quickly with drop in screen on times.

I like the Speck Candy Shell case in white with black effects best. I usually prefer black but the front wrap is black and the white shows less micro scratches that this case is prone to. Nice grip, less slip is a necessity for this wider phone. Excellent fit and drop protection.