iFlash Solo – perfectly reliable iPod/sd-card combos

[chris_s]

I had long resigned myself to using CF cards with Rockbox for perfectly stable operation on iPods but was surprised today to find after some fairly extensive testing that the latest dev build of Rockbox seems to work flawlessly (including USB transfers and database functionality) on an iPod 4G with an iFlash Solo SD card adapter and an 16GB SD card with only two minor code modifications:

- disable DMA (which is necessary on that device regardless of storage method for stable long-term operation)
- always return 0 for ata_disk_is_active in firmware/drivers/ata.c (otherwise the shutdown process will stall and timeout after ~15s) – I don't think this should have a negative effect?

That exact combination of components was extremely unreliable when running Rockbox just ~2 years ago. Apparently there's been some work done on the ata timings (and possibly something else?) since then, specifically with respect to the iFlash Solo?

This actually makes me wonder if it's now safe to order a large (512GB) SD card or whether I will once again run into problems then. Is the type or size of SD card supposed to make much of a difference? I've ordered a 512B Samsung EVO Select card to try my luck with it this weekend. Ideally, the setup would also work on an iPod video . All of this brings me to ask whether there are now *confirmed* combinations of hardware components that work flawlessly together. I.e. a certain iPod with a certain adapter and certain SD card using a recent build (possibly with some minor modifications). What I'm looking for is rock-solid, flawless long-term operation even using the database which my 256GB 4G CF-based Pod (with DMA disabled) has given me over the years. I thought for the longest time that there was no way to achieve this  using SD cards and Rockbox without a lot of hacking, but this recent experience seems to indicate otherwise?

[chris_s]

Success! My Samsung EVO Select 512GB (supposedly identical to Samsung EVO Plus) arrived yesterday and I copied 400GB of songs to it, some using Rockbox’s USB mode and some using the OF, simply because the latter was faster (probably) due to the use of DMA.

In the few hours I’ve tested since then, I’ve had not an inch of trouble. Everything works perfectly so far, including database functionality, Rockbox USB transfer and playback of any transferred files.

Looks like the ATA timings in combination with the power management changes (+x ?) made all the difference. A million thanks to the Rockbox developers involved!

I’ll go back to this post to update it in case I encounter any problems, but so far it looks like I can recommend this particular setup at this time:

Hardware: iPod 4th generation (grayscale)
Adapter used: iFlash Solo (from 03/2018, not sure if there’ve been changes since then)
Cards tested:

• (2021) Samsung EVO Select 512GB microSD (supposedly identical to Samsung EVO Plus)
• Sandisk Ultra 16GB microSD

Build: Current developer build (422aa56243) with modifications as described in the OP

I’ll be testing the adapter and card on an iPod video in a few days to see if it works just as well on that hardware using the latest build.

[chris_s]

I’ll be testing the adapter and card on an iPod video in a few days to see if it works just as well on that hardware using the latest build.

Didn't turn out to be the case, unfortunately. I'm getting data corruption on an Ipod video when doing USB transfers using Rockbox on the latest build. Disabling DMA didn't seem to help, either. Kind of disappointing :/ The iPod 4G on the other hand still works great.