NSA320 - packet loss on U-Boot, slow SMB transfer rates (no replies)

I got another NSA320 it should running with debian but the first thing that I notice:

It looks like I cannont transfer anything via TFTP (U-Boot)
The stock U-Boot only noticed sime timeouts and newer U-Boot versions show
dropped packages and the file (s) never get transfered

NSA320> tftp 0x800000 foo
Using egiga0 device
TFTP from server 192.168.1.112; our IP address is 192.168.1.200
Filename 'foo'.
Load address: 0x800000
Loading: ##Err..(mvgbe_recv) Dropping packet with errors
T #Err..(mvgbe_recv) Dropping packet with errors
T Err..(mvgbe_recv) Dropping packet with errors
T #######Err..(mvgbe_recv) Dropping packet with errors
T Err..(mvgbe_recv) Dropping packet with errors
T #Err..(mvgbe_recv) Dropping packet with errors
T #Err..(mvgbe_recv) Dropping packet with errors
T ###Err..(mvgbe_recv) Dropping packet with errors
T Err..(mvgbe_recv) Dropping packet with errors
T Err..(mvgbe_recv) Dropping packet with errors
Err..(mvgbe_recv) Dropping packet with errors
T Err..(mvgbe_recv) Dropping packet with errors

Retry count exceeded; starting again
Using egiga0 device
TFTP from server 192.168.1.112; our IP address is 192.168.1.200
Filename 'foo'.
Load address: 0x800000
Loading: ##Err..(mvgbe_recv) Dropping packet with errors
T ##Err..(mvgbe_recv) Dropping packet with errors
T #Err..(mvgbe_recv) Dropping packet with errors
T #Err..(mvgbe_recv) Dropping packet with errors
T #Err..(mvgbe_recv) Dropping packet with errors
T Err..(mvgbe_recv) Dropping packet with errors
T Err..(mvgbe_recv) Dropping packet with errors
T ######Err..(mvgbe_recv) Dropping packet with errors
T ##Err..(mvgbe_recv) Dropping packet with errors
...
...
	 5.9 KiB/s
done
Bytes transferred = 302396 (49d3c hex)

after a while it gets transfered.

booting debian doesn't show any things related to this, I have no packet loss while pinging the box from other devices
or ping other devices from this box.
So I decided to see what SMB speed I can get.
On another NSA320 I got 38 MB/s read and 35 MB/s write
With this box only 12 MB/s read and 7 MB/s write were possible

the same two HDDs (raid 0) give 90 - 100 MB/s read and 50 MB/s write in my NSA325v2.

what's going on there?
the syslog doesn't show any bad things.

Edit

it seems that the hdds didn't get mounted but now .. the write speed is only 2 MB/s ;-(

hdparm to the created md0 gives 160 MB/s

Edit 2

putting the device directly to my main system and this doesn't occour

Filename 'foo'.                                                     
Load address: 0x800000                                                                                                     
Loading: #################################################################                                                 
         #################################################################                                                 
         #################################################################                                                 
         #################################################################                                                 
         #################################################################                                                 
         #################################################################                                                 
         #################################################################                                                 
         #################################################################                                                 
         ##################################                                                                                
         6.8 MiB/s                                                                                                         
done

I never had such issues with other devices on the actual router/switch

Edit 3

it seeems that the router/swich has done something wired
changed the pc and nsa320 cable .. and it gets transfered via tftp