Default [Q] Criteria for finding a replacement ROM...?

Here's a noob question for y'all.

What criteria should I be applying when looking for a replacement/upgraded ROM for my tablet? The CPU architecture? The type of processor chip? The kernel version? The EXACT name/model number of my device? A combination of all these with some other ones too?

I recently bought an Odys Fusion 7-inch tablet running JB 4.1.1. According to CPU-Z it is Rockchip RK3066 with ARM Cortex-A9, dual-core 1.5GHz, kernel architecture armv7l, kernel version 3.0.8+.

The device is rooted (see below for a quick summary of how I did it) and I have also made a Nandroid backup of the stock factory ROM on to my PC (details likewise below) but I haven't yet tried a recovery with this file so I don't know if it 'works'.

As my tablet is a fairly non-run-of-the-mill make, and an even more obscure (now discontinued) model name, it is extremely difficult to find any information at all about it on the internet, even on this illustrious forum.

In general, I am fairly happy with this tablet, although I have a Bluetooth problem which I'm hoping will be solved by upgrading to 4.2x or even 4.3 (KitKat 4.4 would be nice but I think that would be beyond the realms of possibility).

The support department at Odys (aka Axdia) told me there would be no further OTA firmware updates. They also hinted that this particular device would be unable to cope with a higher OS version than I already have but I find this hard to believe.

How can I find out what is the highest API level (ie operating system version) my tablet can sustain, based on its hardware/current kernel?

http://forum.xda-developers.com/show....php?t=2108704
For example, I found in this forum the above-mentioned link for Oma's ROM which led me to his Crew RKTablets Genio AOSP 4.2.2 v3.3 – 20.11.2013 ROM which says it is also for the RK3066 and will run on 3.0.8+. Is it safe to flash my Fusion with this as it is intended for an Odys Genio (also no online information/specs)? If I brick my device with an incompatible ROM image, is it irreversible or can I can get back to where I was with my Nandroid backup or with a factory reset? Also, I don't understand what all the other associated downloads on the same web page as this ROM are for, eg format_NAND_fix, extSD_to_NAND, tablet and phablet UIs, homebrew kernel & CC kernel. Anyone care to explain for me please?

Thanx in advance peeps............


Disclaimer: these methods worked for me on my Odys Fusion. They may not work on your Fusion or other Odys tablet or other make of tablet. I put them here for guidance only - use them at your own risk!!

[How I rooted my Fusion: if you don't have the ADB drivers already installed on your PC, search on Google for the file adb-1.0.29.7z and unzip it. Copy from the rktools folder the file "android_winusb.inf" and move it to the usb_driver folder and OVERWRITE the file with the same name already there. Turn on your tablet, and in Settings>>>Developer Options put a tick in USB Debugging. Download from kingoapp.com or CNET the Android Root program "android_root.exe". Connect your tablet to the PC with the USB cable, preferably direct and not to a hub. If it needs the drivers, point it to the usb_driver folder containing that file you just copied. You should now see the ADB drivers in Device Manager. Run the Kingo program on your PC as Adminstrator, it should find after a few seconds the connected tablet, press 'Root' and it will take about 5 minutes. Disconnect the tablet using the Safely Remove Hardware icon in the system tray and unplug the cable. Reboot the tablet. Check the rooting was successful with the free app Root Checker Basic from the Play Store. Don't forget to uncheck USB debugging when you're done otherwise the normal USB Mass Storage operations will not work. This Kingo software can also be unused to unroot at any time you need to in the future.]

[How I made a Nandroid backup: No need to reboot into the bootloader this way but it does require root access. With your tablet on, download the two apps Busybox (free or pro version) and Online Nandroid Backup (H3RRT1C) (free or pro version) by Thomas Otero/Ameer Dawood and install them. Run the latter on your tablet (no connection with PC necessary) but check settings page carefully first. (I intended to do my backup to an empty external micro-SD card but I inadvertently selected the internal SD card. Luckily I had a enough space (5GB in total, 2.1 GB currently in use) to store it there but I'm sure the program would have told me if there wasn't. No problem - after the backup finished, I just copied the whole folder to the micro-SD card and then backed it up on my PC with a card reader and also to my Google Drive account for safekeeping). The whole backup process took about 8 minutes with clear on-screen infos about its progress and it produced a file about 1.1 GB in size which tallies with Settings>>>Storage figures. Afterwards, I uninstalled both apps. Like I said above, I haven't yet tested the validity and integrity of this backup by doing a recovery with it. Judging by the size of the file it is only my system that it has backed up, not my apps or SD card contents; these are all on my PC anyway.]

Example output log of Online Nandroid (some lines removed for reasons of clarity):

Starting backup...
Running with the following commands: -o --utc --storage /external_sd -pd -r
Using ash Shell
##########################################
Online Nandroid Backup v9.51
* A tool to perform a nandroid backup
without booting into recovery.
* It is fully compatible with nandroid.
* Type 'onandroid --help' for usage
instructions.
* Created by Ameer Dawood
##########################################

Starting time: Using busybox from: /data/data/com.h3r3t1c.onnandbup/files/busybox
Checking for root permissions...
Root permissions acquired!
Analysing battery level...
Sufficient battery available!
Checking version of BusyBox installed...
BusyBox version 1.20 or above installed!
.
.
.
.
Backing up the old backup for replace operation... 100%
Backing up /boot........... 100%
Backing up /recovery........ 100%
Backing up /kernel........... 100%
Backing up /system............................................ ................................... 100%
Backing up /data.............................................. ................................. 100%
Backing up /cache... 100%
Backing up /.android_secure............................ 100%
.
.
.
.
Finish time: Online Nandroid Backup Completed in 8 minutes 18 seconds!
exitcode [0]