Privacy Enhanced Linux for Pi 3 Update
HDMI 1080p Edition

http://tinyurl.com/pelinux3
(10.3 MB firmware partition ONLY, keep your data)

10278927 Aug 29 01:05 firmware.zip
md5sum f67dea931d9f4812ba155f551e4f9967

Firmware is on a FAT (old Windows) partition so just delete/replace what's there with the contents of this zip, no permission issues. The config.txt file now defaults to 1080p but you can revert back to the old behavior by commenting out two lines. This package does NOT upgrade the kernel from the very reliable 3.18 ARMv7 one you've been using. This package IS backwards compatible so if your Pi 3 goes up in a puff of smoke from lack of heatsinks just pop the card back into your trusty Pi 2. I'm still using the older Pi 2 firmware in one of mine though as it's optimized and boots a second faster. No drivers for the Pi 3's built-in WiFi and Bluetooth however, you'll have to keep whatever USB dongles you're currently using, sorry.

Time to Make a Backup

Before any potentially catastrophic operation, like updating from Debian 9 backports, it's always a good idea to make a full backup. I do so by putting my microSD card in a USB 3.0 card reader and:

sudo dd bs=512 if=/dev/sdb of=mypi.img

I get around 65 mb/sec backup speed out of my UHS card. To restore just reverse input file (if) and output file (of) parameters. The backup img file will be the same size (32 gig card = 32 gig file) so make sure you have room and a compatible file system (NTFS is OK, FAT has a max 2 GB file size).