Rockbox Technical Forums

Support and General Use => Hardware => Topic started by: Gouty on May 02, 2019, 08:57:27 AM

Title: iPod 4th gen SD incompatibility
Post by: Gouty on May 02, 2019, 08:57:27 AM
I recently upgraded the storage on an old iPod 4th Gen with a broken HD to a 128GB SD card using a 50pin -> Compact Flash -> Compact Flash SD Adapter -> SD Card.

The original apple firmware works great and I have a load of songs currently syncing to it.


Rockbox installs just fine, but once you boot into it, it has major issues reading files.

Plugging it into a computer brings up the HID interface after about a 30 second freeze, but it does not appear as a device on the computer and cannot be ejected, if you disconnect it you get a "panic mount 0 error" and the iPod must be restarted.

I copied some music files to it when it was booted into apple firmware and then tried to play them with Rockbox and this resulted in:

Code: [Select]
*PANIC* dc_writeback_callback() - Could not write sector 80326 (error - 4)

I tried it with a 64GB card of a different manufacturer (same class) and it had the same issues.  I tried an older 2GB SD card and Rockbox worked just fine.

After doing a little research it seems that I am not alone with this issue, but no-one seems to have figured out what causes it or how to fix it?,52746.0.html,52370.0.html

Anyone know if there is any rhyme or reason to the compatibility issues? Is it an issue with Class 10 cards? Has anyone tried the newer speed classes (e.g. UHS 3?)

I'd really like 128GB of storage and working Rockbox, but I can't fork out for a 128GB CF card which are like 4 times the price.

I've got a 64GB class 4 card on the way (the largest I could find) and I'll be testing an iPod mini in a few days too.

Edit: also posted to the Rockbox subreddit (
Title: Re: iPod 4th gen SD incompatibility
Post by: chris_s on May 04, 2019, 05:37:10 AM
I've only had good luck with CF cards (and hard drives, obviously) on an iPod 4G. In both cases I additionally had to disable UDMA to ensure completely flawless long-time operation. Otherwise, sooner or later FS corruption would occur, which becomes especially noticeable when using the DB where you'll be asked to re-initialize it out of the blue.

Yes, CF costs a little more, but for me it was worth it. I actually have the problem that I'd like 512GB of storage space, which simply isn't available at the moment.

Let us know if you find something that works.
Title: Re: iPod 4th gen SD incompatibility
Post by: Gouty on May 06, 2019, 08:10:16 AM
Thanks for the info.

I had assumed that the mini IDE hard drives wouldn't be available any more, I was quite surprised to see you could get an 80GB drive for about the same price as a 128GB SD card.  I probably should have gone with that for the compatibility.

I tried a 64GB Class 4 SD card in it, and it had the same issues.

I guess I'll just stick with the default firmware for now and suffer the decreased life for the SD card.
Title: Re: iPod 4th gen SD incompatibility
Post by: Gouty on May 15, 2019, 02:18:25 PM
iPod Mini has the same issues with SD cards. I managed to get a compact flash card for a reasonable price and it works great!

How do you disable UDMA? I can't seem to find any information on it
Title: Re: iPod 4th gen SD incompatibility
Post by: saintruggler on November 28, 2020, 01:33:21 PM
Can anyone on this thread report which exact model(s) or compact flash cards are successful and stable running Rockbox on the iPod 4th gen? Mine is a 4g 20gb mono. As others have noted, I am able to run Apple firmware just fine using the CF-to-SD adapter. However, I prefer Rockbox and really cannot abide gaps between tracks.

Old thread, but please report back on fully functional CF cards (model, capacity, etc.) in the rockbox'd iPod 4th gen.

Title: Re: iPod 4th gen SD incompatibility
Post by: saintruggler on December 04, 2020, 02:25:54 PM
Updating to answer my own question. I purchased the Transcend 128gb 800x CF card (MFR #TS128GCF800) and it seems to be working fine in my iPod 4g monochrome, with DMA disabled. Hopefully this info will help someone else along their journey.