Android and its ROMs
Yes, ROMs. Not Romulans, as this is not Star Trek. Alas.
A while ago I got an Android update on my smartphone. It was for Android 4.4.2. I installed it and I was not a happy camper: suddenly only Google's own apps could manipulate the SD card! The trick would be to ROOT the phone (breaking it open, in a way, to give me all the permissions again). It was quite an experience.
How to root your phone: first you need a Recovery Rom. Best known are CWM (ClockWork Mod) and TWRP (no idea, I didn't use this one).
I used Philz Touch CWM rom. Note: find the version that works for your phone. Mine was N7100. Make sure you pick the right one. Please use Google or Bing or so to locate this file, there are many versions. Search for "Philz Touch recovery tar md5". You will also need a Windows-program called Odin. This is what you need to put the recovery rom on your phone. The last one I know of is Odin3 3.09.
Online you can find information how to do this, but the quick rundown is: run Odin. Point the 'AP' location to the tar.md5 file with Philz Touch Recover. Put your phone in DOWNLOAD mode. Connect USB cable. Wait for Odin to recognise the phone. Press start. Wait until Odin reports Success.
Once you did that you can locate a ROM you want to put on the phone. The one I finally had success with was the TigraRom v4. This one runs Android 4.3, is rooted and gave me back read/write access to the SD card. This is the one I'm currently running. To install a new ROM, first backup your stuff. Then make sure you've backed up your stuff. Find the ROM that works for your phone. Really, read that again. Download it and put the ZIPfile on your phone or on the SD Card. Boot your phone into Recovery mode (usually Volume-up and Power, but my phone also needed the Home button pressed so look that up for your phone). You'll be put into Philz Touch Recovery.
Start sweating: select Wipe Data/Factory reset and confirm you want to do this. return to this menu (is easy). Select ADVANCED and select Wipe Dalvik Cache. Confirm.
Then select 'Install Zip'. Locate the zipfile on your device and make it so. This is where the magic happens: the new ROM is loaded onto your phone. After that: reboot system now. That's all there is to it. After that it's up to you to find if the ROM works for you. I found Tigra to work after 8 or 9 disappointments. Flashing a ROM gets easy after a while, trust me. ;-)