[U-Boot] SD card on the GuruPlug

[Ludovic Courtès]

Hello,

The GuruPlug has an internal μSD card reader, which it views as a USB
device:

--8<---------------cut here---------------start------------->8---
Marvell>> usb start
(Re)start USB...
USB:   Register 10011 NbrPorts 1
USB EHCI 1.00
scanning bus for devices... 3 USB Device(s) found
       scanning bus for storage devices... Device NOT ready
   Request Sense returned 02 3A 00
1 Storage Device(s) found
Marvell>> usb tree

Device Tree:
  1  Hub (480 Mb/s, 0mA)
  |  u-boot EHCI Host Controller 
  |
  +-2  Hub (480 Mb/s, 100mA)
    |   USB2.0 Hub 
    |
    +-3  Mass Storage (480 Mb/s, 500mA)
          USB Storage 000000009909
--8<---------------cut here---------------end--------------->8---

However, with a μSD card in, with a valid MS-DOS partition table, it
apparently fails to read from it:

--8<---------------cut here---------------start------------->8---
Marvell>> usb part
## Unknown partition table
--8<---------------cut here---------------end--------------->8---

Conversely, “usb part” works as expected with a USB key or USB disk
plugged in.

Does anyone have experience with it?  Any idea how I could further debug
the problem?

Thanks,
Ludo’.