Troubleshooting • RPi5 + SD Card Extension

For my project I need to extend the SD Card. For this purpose I bought a UHS-II/UHS-III SD extender, even though the RPI5 "only" supports UHS-I, I choose this model because it has a method to fasten the receiving part of the extender.

When I attempt to boot the official Lite OS with the extender, everything seems fine for a while, but eventually I'm starting to get messages like this:

Begin: Running /scripts/local-premount ... Begin: Resizing root partition... ... [7.289339] I/O error, dev mmcblk0 [cut]
[ 7.808055] I/O error, dev mmcblk0, sector 16672 op 0x0:(READ) flags 0x80700 phys_seg 7 prio class 2
[ 8.286128] I(O error, dev mmcblk0, sector 5832576 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
[ 8.419592] I(O error, dev mmcblk0, sector 5832576 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2
[ 8.429132] Buffer I/O error on dev mmcblk0, 148988, async page read
...
and then the booting grinds to a halt

The Sd card is the official 64GB Raspberry one and it boots fine without the extension.

Some info about the extension. It is a 10cm long model, B33SH from ADT-Link store on AliE

Some questions:
Does it work to extend the SD card in Rpi5?
Are there known working extenders that doesn't sacrifice performance?

Statistics: Posted by pike2k — Wed Dec 24, 2025 3:47 am — Replies 0 — Views 42

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