Here you will find a clear exposition for each iPod Classic Generation and the storage limitations.

This subject need some definition: I invite you to visit the Troubleshooting section @ this vendor (I have no interest into those products and yes, I bought a couple of those cards) https://www.iflash.xyz/troubleshooting-guide/ On this site you also find in depth information such as iPod Generation Compatibility here As a footnote I also like to point the Red X screen for failing to Open the Device: it happened to me using a ZIF SATA card and it should be clear that this issue is coming because of some mistakes made on connecting the card, either by a faulty ribbon or as I was able to verify, just because I thought the ribbon's contacts on the the card had to face downward toward the card, while it worked only if I reversed it. To double check it you should reboot the iPod (press MENU + SELECT) and quickly enter the diagnostic mode (press BACK<< + SELECT) go to Manual Test / I O / and verify you can actually open the storage device: if it fails to open you have a probable chance of a defective ribbon, or...

I used a small bended tweezers and I just pressed when I found the recess and by pressing and move around the closed tweezers I dug a perfect round hole in the label to show the screw. Thanks for the tip!

The only difference I know regarding the A1398 is the display connector with a different number and position of the pins:

# A1398 Early 2013

# A1398 Late 2013/2014

# A1398 2015

the display connector and display circuit board is different on each of these, so if you want to swap the motherboard you should also swap the LCD assembly.

I wonder about the four cables / connectors used on both speakers' sockets: anyone knows about their functions?

I suspect there are two poles just for Ground while the other two are for Hi/Lo freq.

Is this just overengineering? Are two cables as seen in oem speakers good enough?

It happened on a 2015 Macbook Pro it only downloaded the "stub" Mojave installer: iirc the Mojave is still supported on that machine and it looks like Apple is now adopting an MS tactic to distribute their OS by downloading a small executable that will eventually connect to their servers and update the OS.

You will not be able to upgrade if you are not connected to the internet.

At this moment I cannot even connect to the App Store from a Mountain Lion install... >B{