Since Jessie's last updates to add a few things like OpenGL Graphics Routines, many people have complained that making an update that forces the operating system to only boot one system compared to the others (in this case an R-Pi2 to a Model B+) was counter intuitive to the “1 child / 1 computer in every nation” mantra. A teacher in Zimbabwe could have a R-Pi2 and the children in her class have the original model B; when the teacher updates the SD for a student’s machine on her machine, it fails to boot (mostly with “ELF” and Configuration File Failures). At this point the teacher can’t do anything as she does not have the cloning capability in both software and hardware. Sure, there is the ‘dd’ in Linux to clone an SD, she also needs a USB to SD converter box, a cable for it, and understand how the dd command works.
 
Thus Debian and the Raspberry Foundation rushed more intelligent releases of Wheezy and Jessie behind the current release of Jessie, which did not update the kernel or other software but made the boot process intelligent. Now the boot sequence checks to see what R-Pi it is on and it goes ahead checking the configuration files to compare what R-Pi created them. If it is the same kind of R-Pi (like a SD card coming a Model B+ and being installed onto another Model B+), the boot process is very fast. But if the boot process sees that if it came from different R-Pi (like a SD card coming a R-Pi2 and being installed onto a Model B+), the boot process takes a minute or two longer as configuration files are being rewritten to accommodate Raspbian Linux for the R-Pi being booted on.
 
What they did saves a lot of headaches for End Users and minimally skilled Technology Educators. To get it, one has to update their current versions of Wheezy or Jessie by having the R-Pi online and typing “sudo apt-get update” in the console terminal. Wait a few minutes and it is done. Now you will have a Raspbian Linux of Wheezy or Jessie that is universal to what R-Pi’s you may have. Just note that when you change R-Pi’s on the SD, it will take longer to boot; but keeping it on the same R-Pi it will boot very quickly. The problem here is that each SD card has to be updated individually for it to work.
 
So back to me…
 
In updating Wheezy (again), this time it took in the universal boot process and made it universal for that R-Pi the SD Card is put into. The problem before of not booting on another R-Pi’s was “repaired.” So my observations on that are as stated above – switching from different models of R-Pi’s was slower as the configurations files were being rewritten during boot, while booting on the same R-Pi the boot process was a lot quicker than before. Before the update, the booting process was slow. I can speculate that in the past the Model A/B and Model A+/B+ are so much alike that you can (and I often did) switch the SD card between them and there were some adjustments being made to the config files to make it boot on any of these 4 R-Pi’s, but that process took a lot of time. At the same time, the update before the current one, only made it bootable for R-Pi only. Though the boot process was very fast, it was stuck on the R-Pi type it was updated on. The current update fixes this issue with a universal boot.
 
Believe it or not I always thought that the slow booting process was because I was using Class 4 SD cards. I do have Class 10 SD cards, and they do boot a lot faster than the Class 4s without the updates. But now the Class 4s boot faster than the Class 10s! Since I have not updated the Class 10 SD cards yet, I can imagine that the booting speed will be like when I do update them!
 
So now I have 1 SD Card with an updated Wheezy and 1 SD Card with an updated Jessie on them, and both are Class 4 SDs which are a lot faster than the non-updated Wheezy on the Class 10 SD!  But now there is another problem.
 
In case you have noticed, the Raspberry Pi (software) Store is closed. Though most of the software on the R-Pi Store was free, there were some that were not, and payment was made through some European bank. Issues of currency exchanges were such a problem that the bank they were using started to refuse to take payments. This was further heighten by the EU banking system to stop accepting non-EU currency because of failures in currency exchanges on the global scale. There are a lot of poor nations out there trying to get across the digital divide and they cannot afford to buy software and hardware. Using Open Source Software that is free for anyone is a major solution for them. Personally, there was a lot of software there I was interested in – all of it for free. Now where can one, like myself, get all this software we need?
 
Jessie was given the Open Libre Office Suite, which is great to have. Before you had to connect to the Raspberry Pi Store and download it and install it (a must do for Wheezy users). But having Open Libre means that you need a 8GB SD card in order to fit Jessie onto a bootable SD card. Minimal Jessie and Wheezy can fit onto a 4GB SD Card as open Libre is not installed on them. But now you cant get Open Libre if you want it on Wheezy or minimal Jessie. And this is true for a lot of software for the Raspberry Pi, not just for Open Libre.
 
My only recourse is to contact the Raspberry Foundation and see what can be done.
 
Thing for you to do:
 
1) Connect your R-Pi to a network and update the Raspbian on it. This will greatly enhance it and make it able to universally boot across the R-Pi Models.
 
2) Have a couple of SDs and have one for Jessie and one for Wheezy.
 
Note:
 
On a non-updated Raspbian like Wheezy or Jessie, it can boot on any R-Pi you put it on, but it takes a long time for the boot process to happen. The original update screws this up for Raspbian to boot on only 1 type of R-Pi Model though the booting process is now a lot faster. The current update fixes this by making it boot to any R-Pi you put it in and the boot process is still faster if you do not change R-Pi's. In changing R-Pi's, the boot process takes longer to rewrite the config files but it is still faster than the original non-updated Raspian.
 
I have tested the updated Wheezy and Jessie I have on my Model B, Model B+ and R-Pi2; with the update being done on the R-Pi2. They work as stated.