[Galaxy S III Mini Q&A, Help & Troubleshooting] HattoriShinsan:
Hi everyone, I spent all day trying figuring this out, even if probably the solution was really stupid, so I thought of doing a little post for future reference. If you have no time for my babbling, feel free to go to the short version (I wanted to put a link here, but I still have to learn how to do it and it's almost dinner-time...). If this post happens to be a duplicate feel free to remove it.

=== Whole story ===​

A week ago I got a Galaxy SIII mini N (GT-I8190N) and just kept it that way because I didn't had a win pc to use Odin. Yesterday I finally came back to my parents, powered up the win machine and followed an awful lot of different guides to manage to install the Macław CM 10.1. So, for short: installed CWM touch trough Odin, installed the root zip trough CWM and finally installed CM 10.1 & Gapps trough CWM. Here I did my first mistake: the first thing I did after installing CM was formatting internal and external SDs. Where the Nandroid backups of the working Samsung firmware were.

After some experiments I decided to go back to Samsung stock (reason 1: no gtalk, only hangouts, reason 2: NFC support still in development, reason 3: trying to restore SMS from a SmsContactsBackup I (luckily) had I messed up the SMS DB so much the app couldn't start). NOTE: Macław's ROM is amazing, I'm surely going to try it again when NFC support comes up. Sadly, I am an idiot who thinks he knows better so I ignored all the warnings of doing a wipe of data/cache and restoring the Samsung original recovery. I just went to Kies for a "Firmware upgrade and initialization" instead.

The result was a disaster. The phone rebooted but hanged at the Samsung animated logo. After a lot of hanging I decided to redo a Kies firmware upgrade. Obviously I had no luck. So I switched to Odin, took the image Kies downloaded (since I didn't want to wait an hour and an half to the download from unofficial sites) and flashed. And flashed. And flashed. Always without success. After a little bit I decided to try changing Odin options (repartition, NAND erase etc). Still nothing. So I started trying all the guides out there (here?): repartitioned with a PIT file, reflashed a CWM, reflashed stock recovery, various combinations in different orders of all the "solutions" above... You guessed right: nothing worked.

Since I read somewhere that there are Galaxy have 25 partitions (what the ****???) and saw that Odin was flashing only 8 or so I decided that something some the other partitions was missing, so I switched to Heimdall. Since the Win version didn't want to start, I did a fresh Ubuntu 13.04 install (lucky for me I happened to have an empty HD waiting to be installed on the server that I could use for an afternoon :P), installed Heimdall, started figuring out how it works, realized I needed a custom-made package (nowhere to be found, apparently), started looking into the partition scheme to understand where the problem could have been... Finally I realized my skills are a tiny little bit inadequate for that and found a reference somewhere to a "hard reset".

In all this it never occurred to me to try and enter Samsung recovery. The first thing I noticed was that it didn't start right away with VolUP + Home + Power, but I had to keep them pressed a lot longer than what it's needed to go in download mode. In practice the SIII mini logo went up two times before showing the android with the open belly. Then finally the recovery appeared, I navigated to wipe data and cache with the volume buttons, accepted with the power button and rebooted. Thus I finally had a Samsung animated logo that was followed shortly by an "installing applications" loading bar and the first start configuration tool.

So, what I learned today:

1) Samsung tools are not necessary evil

2) if you don't understand what you're doing and you're doing it anyway, be prepared to suffer

3) we probably need a unified guide/troubleshoot the whole community can edit (wiki-like). Threads are great, but it's really easy to miss the obvious (for the whole time I was sure it was a bootloader problem, never occurred to me that there could have been some data left... also because I did a NAND wipe through Odin and I thought that was supposed to wipe personal data...) and often propose a solution without explaining the rationale behind it. I'm sorry if there's something like that out there somewhere, I wasn't able to find it :(

Thanks to you that bore my babbling :D

And now it's time for:

=== The short version ===​

Problem: I messed up doing a Kies reset after installing a custom rom (CM10.1) without the dues precautions; the result was a phone caught in an endless loop at the Samsung logo. Installing firmware with Odin didn't solve a thing.

Solution: I booted in recovery (volume up + home + power) and wiped data and cache. After that I rebooted and waited a little bit, a progress bar appeared and everything was fine (well phone was at factory default but at least now it's working :) ).

I hope all of this could be useful to someone