Probe ALL LUNs

[probono]

Thanks for the quick reply. Still I can only use one out of four slots of my USB card reader. How can I check whether all LUNs are activated?

cat /proc/scsi/scsi

Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
  Vendor: SONY     Model: CD-RW  CRX140E   Rev: 1.0n
  Type:   CD-ROM                           ANSI SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 00
  Vendor: IC       Model: USB Storage-CFC  Rev: 301b
  Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 01
  Vendor: IC       Model: USB Storage-SMC  Rev: 301b
  Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 02
  Vendor: IC       Model: USB Storage-MMC  Rev: 301b
  Type:   Direct-Access                    ANSI SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 03
  Vendor: IC       Model: USB Storage-MSC  Rev: 301b
  Type:   Direct-Access                    ANSI SCSI revision: 0

So far, it looks just as before.
But:
scsi_info /dev/sdc

SCSI_ID="0,0,2"
MODEL="IC USB Storage-MMC"
FW_REV="301b"

That last thing wasn't there before your hint. But still I cannot mount the MMC card:

mount /dev/sdc1 /mnt/test
mount: /dev/sdc1 is not a valid block device