The Fiat / Abarth 124 Spider entertainment system (CMU) firmware is somewhat lagging behind the MX-5 equivalent . Here's how you update it to resolve that oversight ...
In fact, Fiat haven't released *ANY* firmware updates for the 124.
However, it *IS* possible to update our Fiat / Abarth cars to (almost) the latest Mazda firmware, and still have the system look and act like a Fiat / Abarth.
There are, of course, a few caveats to that statement, so first it's necessary to answer the following questions to decide which firmware can safely be applied to your CMU.

1) Have you already performed any modifications to your CMU?
2) Do you use an Android (Samsung, Motorola, Huawei etc.) or iOS (Apple) phone?
If you answered Yesto the first question and Android to the second, then there's a thrid question which needs to be answered:

3) Have you installed any add-on version of Android Auto (AA) to your CMU
If you answered Yes to the third question, you probably know everything that's going to be included in this guide already :)
With those all answered, there's basically 2 main options:
    • Leave your CMU on your installed firmware version (only if using AA as an add-on)
    • Upgrade your CMU to a much newer version (70.0.100) firmware

Presuming we're going to go ahead and perform an upgrade to firmware v.70, there's a few more things we need to do as pre-requisites - these are needed because Mazda have, in their latest firmwares, taken steps to block users from modifying their CMUs. It is very important that you follow the next steps in order and do not skip any of them, even if some seem to be repetitive of steps previously taken.

1) Firstly we need to know what firmware version the CMU is running at the moment. Go get this infomation, go to the Settings > System > About > Version screen. Your car is likely to say 56.00.530 if it is an European car or if it is a North American car. So long as it says one of these two numbers, we're good to proceed to the next step. However, if the firmware version on your car is anything higher than v 59.0.0.xxx, you'll probably need to stop here and seek further advice.
2) Download the software we'll be using. We'll need the following applications / files  to fully update to version 70 & retain our Fiat / Mazda branding
We'll also need at least one USB memory stick - ensure it is larger than 4GB in size and formatted in FAT32

3) Extract the files from the ID7 Recovery Tools file and copy them to the root of your USB memory stick. Ensure there are no other files on the memory stick.
4) Go to the car and press the start button *WITHOUT* pressing the clutch or brake pedal to put the car into accessory mode. Insert the USB stick into one of the USB ports in the car and wait for the CMU to display an installation screen. Follow the instructions and allow the ID7_Recovery scripts to be installed into the CMU. Once the installation has completed, the CMU will reboot. Allow this to happen, removing the USB stick when told it is safe to do so.
5) To ensure the step above worked, as it is probably the single most important step in this entire process, re-insert the same USB memory stick into one of the car's USB ports again and wait for the installer to start. This time you are looking for the installer to say "Update" rather than "Install" - this iindicates that the ID7_Recovery script has already been installed. If you do not see Update, do not go any futher at this time!
6) Now is the time to install the actual firmware update. This is quite a long process, but we have produced some instructions to help carry it out. It is important to read all the instructions before starting, especially taking note of which steps need to be ignored. I strongly suggest you print these seperate instructions and take them to the car with you.
7) Having installed the firmware update and ensured your firmware is now on vesion 70.00.100 as indicated above, the final part of the update process is to re-Fiat-ize / re-Abarth-ize your firmware and to re-enable the (currently broken) Navigation application. To do this, you will need to extract and copy all the files from the Mazda to Fiat Converter file downloaded previously to a balnk USB memory stick and install this in to your car's CMU.
8) Start the installation process in the same way as was done in step 4) above. Read al the instructions and options displayed and choose either the Fiat or Abarth options presented.
9) Once all the updates have installed and the CMU rebooted, you should now see the Fiat / Abarth logos rather than any Mazda ones; and your navigation application should work perfectly.