Nice pics mypenneys, do you happen to have a pic of the PCB under the shielded part?
It would be interesting to know what actual CPU they are running.
I don't actually have a ctx3030 myself, a friend of mine has just ordered one, and I stumbled across this thread while searching on the internet, and the title caught my eye.
Well here's what I deduced so far......
From the picture you posted of the bottom of the main pcb, I'd hazard a guess at the unpopulated 10 pin header at the top of your picture is a JTAG debug interface.
It also looks like the 3 pins at the bottom could the a serial uart.
I downloaded the firmware from minelabs site: http://www.minelab.ie/__files/f/289343/CTX%203030%20Software%20Upgrade%20August%202016.mlb
I haven't spent a huge amount of time looking at this, I only downloaded the file last night.
Here are some initial observations.
System runs linux, uses an arm processor, and it seems to use redboot for the bootloader.
There's a PK (zip) header (bytes 50 4B 03 04 14) in the mlb file at offset 0x2f700, removing the bytes prior to this, and rename to .zip will allow you to extract the rootfs and uImage.
If you use binwalk under linux you can extract the rootfs, and uImage from the file.
Extracting the rootfs was a little bit of a challenge as it uses ubifs, so I had to find an extractor.
I used ubireader written by jrspruitt which is available on github.
Kernel build line:
Linux version 2.6.28-317-g208065e-g391fcf2-dirty (jenkins@linux-6cu5) (gcc version 4.1.2) #1 PREEMPT Fri Aug 12 16:49:18 CST 2016
The kernel bootline seems to be
noinitrd console=ttymxc0 root=/dev/mtdblock2 rw ip=off
Which is why I mentioned the uart looking port on the main pcb, hooking this up to a ttl serial converter may give you a shell on the device...
Inside the rootfs, the system runs busybox, and uses QT for the display driver.
There are four main executable files which run the whole detector.
22/01/2017 01:11 1,259,692 pod
22/01/2017 01:11 32,648 audio
22/01/2017 01:11 60,208 debug
22/01/2017 01:11 37,176 detector
All of these are standard elf files.
I recommend IDA (disassembler) if you want to have a look at the files / disassemble them.
The pod file which appears to be the main program also holds the icons for the system as embedded png's
I managed to extract them (see below).
So, that's pretty much what I did last night