In the last years I read already a few times about the iPod now being super upgradable to an SSD or micro SD nearly as big as you want.
Source: https://hackaday.com/2022/02/16/classic-ipods-are-super-upgradeable-in-2022/
So I looked up the parts already a while ago on Amazon, but they were pretty expensive, so I decided to wait or don’t do it. But a few weeks ago I saw one part being available on AliExpress, so I instantly looked up the other parts and ordered (round about 30€). See below for part links (just for example). Last week all parts arrived and I started my project and put everything together. If you also want to do that, here is a link on how to dis-/assemble the iPod:
As I wanted to minimize the risk for shorts and loose parts inside, I 3D-printed two thin layers of TPU to place between adapter and backplate and between adapter and board.
I then assembled everything (without closing the case!) and restored the iPod using my old MacBook (2013 - running macOS BigSur). I restored the partition in finder and then restored the iPod with Apple Music. Tried with windows first, but couldn’t get it to work. Works like a new one now! Definitely recommend if you have one laying around.
Ask me if you have any questions :)
The printable case I made is available for free here:
https://www.printables.com/de/model/554008-ipod-classic-5g-30gb-case-with-hexagon-back
Parts:
CF to microSD Adapter:
CF Upgrade Card:
Shell replacement (optional):
Edit/Update:
I made a dock for it, that works with the charging/sync cable and fits my case.
Here are the print files for the dock:
https://www.printables.com/de/model/555680-ipod-dockstand-for-gorroths-tpu-case
Edit/Update 2:
I now also made a storage/travel box you can 3D-print available to download here:
https://www.printables.com/de/model/565265-ipod-classic-5-box-inkl-kabel-management-airtag-ed
Look at my post on the box here for details:
Why did OP pick a $6 one over a $30 one?