Hi,
I am currently running ARM Linux 3.1.10-13 on my Pogoplug series 4.  I am trying to mount 4TB hard drives that have been formatted HFS+ (under OS X 10.8.2), journaling has been disabled, GPT partition.  I have installed all current system and filesystem updates.  I have also installed udev-automount.  When I attempt to mount 4TB HFS+ USB hard drives, the hard drive will not mount.  This is what is reported in /var/log/messages.log:
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Dec 31 19:00:07 localhost kernel: [   18.005858] scsi 1:0:0:1: Direct-Access     DataTale RSM2QJ2               PQ: 0 ANSI: 2 CCS
Dec 31 19:00:07 localhost kernel: [   18.006772] sd 1:0:0:1: Attached scsi generic sg1 type 0
Dec 31 19:00:07 localhost kernel: [   18.020724] sd 1:0:0:0: [sdb] 7814037152 512-byte logical blocks: (4.00 TB/3.63 TiB)
Dec 31 19:00:07 localhost kernel: [   18.021564] sd 1:0:0:0: [sdb] Write Protect is off
Dec 31 19:00:07 localhost kernel: [   18.036530] sd 1:0:0:1: [sdb] Very big device. Trying to use READ CAPACITY(16).
Dec 31 19:00:07 localhost kernel: [   18.202394]  sdb: sdb1 sdb2
Dec 31 19:00:07 localhost kernel: [   18.220468] Alternate GPT is invalid, using primary GPT.
Dec 31 19:00:07 localhost kernel: [   21.950853] hfs: invalid secondary volume header
Dec 31 19:00:07 localhost kernel: [   21.950874] hfs: unable to find HFS+ superblock
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I can plug 2TB HFS+ formatted hard drives (journaling disabled), GPT partition, into the Pogoplug back USB ports and the drives will be mounted R/W without issue.  Thoughts on how to resolve this?
			
				