Hello dear AOS4 betatesters:
Would like to use this official AOS4 feedback forum to report a problem and show an example of working communication between betatesters and simply user like me 

Please take this information and fill a bugreport on bugzilla for this problem:
- SAM440ep and AOS4.1U2.
- USB key FAT32 16go OCZ, with a just 1 drawer with 10 files on the drawer and just one file on the root (mean empty at 98%).
I launch memguard and launch, with dopus4, a copy from the HD to the USB key, factory formatted in FAT, with just one file to be copied on the key. The size of the file is 350mo.
dopus4 copy well the file untill maybe 50% and a memguard hit appeared.
the USB recognize again the key and and aos4 show me a read error on block xxx.
cancel and USB recognize again the key and aos4 show me a read error on block xxx.
and so on but by chance at a moment, I was able to save the memguard output.
Please, please, fill the bugzilla with this information. this error exist with AOS4 and AOS4.1U1 and with AOS4.1U2.
You have understand that this error is not new for me because encountered more than one time.
I would like also to said that this copy error appeared maybe because memguard is running but It's well OHCI pointed by memguard.
SFS: Warning: Task 0x5fe5a070 ("OHCI Controller Task Unit 0") called DoPkt()
SFS: Warning: Task 0x5fe5a070 ("OHCI Controller Task Unit 0") called DoPkt()
SFS: Warning: Task 0x5fe5a070 ("OHCI Controller Task Unit 0") called DoPkt()
SFS: Warning: Task 0x5fe5a070 ("OHCI Controller Task Unit 0") called DoPkt()
SFS: Warning: Task 0x5fe5a070 ("OHCI Controller Task Unit 0") called DoPkt()
MEMGUARD HIT - "OHCI Controller Task Unit 0" (5fe5a070)
allocation of 8192 bytes by AllocVecTagList() failed
 0: 6f611be4 5fe3ad90 00000000 01ca97c4 00002000 5fe3ae18 59cb2c58 59563048
 8: 00002000 00000008 01ca97c4 0000207f 24000082 00000000 00000000 00000000
16: 00000000 00000001 59563048 5a5ecb50 5fe23680 00002000 01e70000 5ff9fb40
24: 00000000 00000040 59c749a8 5fe954c8 00000000 00000040 00000002 00000003
----> 6f611be4 : "MemGuard" segment 0005 offset 8bdc
----> 01ca97c4 : "Kickstart/kernel" segment 0001 offset 497c0
----> 01ca97c4 : "Kickstart/kernel" segment 0001 offset 497c0
----> 01e70000 : "Kickstart/newlib.library.kmod" segment 0001 offset 061c
LR    014136f0 : "Kickstart/kernel" segment 0000 offset 136ec
CTR   6f611be4 : "MemGuard" segment 0005 offset 8bdc
Stack backtrace:
----> 014136f0 : "Kickstart/kernel" segment 0000 offset 136ec
----> 018c7abc : "Kickstart/ohci.usbhcd" segment 0000 offset 5558
----> 018c5274 : "Kickstart/ohci.usbhcd" segment 0000 offset 2d10
----> 018cc2c8 : "Kickstart/ohci.usbhcd" segment 0000 offset 9d64
----> 018cc448 : "Kickstart/ohci.usbhcd" segment 0000 offset 9ee4
----> 018c9d74 : "Kickstart/ohci.usbhcd" segment 0000 offset 7810
----> 0141587c : "Kickstart/kernel" segment 0000 offset 15878
Disassembly:
 014136ec: 4e800421     bctrl   
 014136f0: 80010084     lwz     r0,132(r1)
 014136f4: 38210080     addi    r1,r1,128
 014136f8: 7c0803a6     mtlr    r0
 014136fc: 4e800020     blr     
MEMGUARD HIT - "OHCI Controller Task Unit 0" (5fe5a070)
allocation of 16384 bytes by AllocVecTagList() failed
 0: 6f611be4 5fe3ad90 00000000 01ca97c4 00004000 5fe3ae18 58f6dea8 59030040
 8: 00004000 00000008 01ca97c4 0000407f 24000088 00000000 00000000 00000000
16: 00000000 00000000 59030040 5a1550c0 5fe23700 00004000 01e70000 5ff9fb40
24: 00000000 00000040 59c749d8 5fe954c8 00000000 00000040 00000081 00000003
----> 6f611be4 : "MemGuard" segment 0005 offset 8bdc
----> 01ca97c4 : "Kickstart/kernel" segment 0001 offset 497c0
----> 01ca97c4 : "Kickstart/kernel" segment 0001 offset 497c0
----> 01e70000 : "Kickstart/newlib.library.kmod" segment 0001 offset 061c
LR    014136f0 : "Kickstart/kernel" segment 0000 offset 136ec
CTR   6f611be4 : "MemGuard" segment 0005 offset 8bdc
Stack backtrace:
----> 014136f0 : "Kickstart/kernel" segment 0000 offset 136ec
----> 018c7abc : "Kickstart/ohci.usbhcd" segment 0000 offset 5558
----> 018c5274 : "Kickstart/ohci.usbhcd" segment 0000 offset 2d10
----> 018cc2c8 : "Kickstart/ohci.usbhcd" segment 0000 offset 9d64
----> 018cc448 : "Kickstart/ohci.usbhcd" segment 0000 offset 9ee4
----> 018c9d74 : "Kickstart/ohci.usbhcd" segment 0000 offset 7810
----> 0141587c : "Kickstart/kernel" segment 0000 offset 15878
Disassembly:
 014136ec: 4e800421     bctrl   
 014136f0: 80010084     lwz     r0,132(r1)
 014136f4: 38210080     addi    r1,r1,128
 014136f8: 7c0803a6     mtlr    r0
 014136fc: 4e800020     blr     
Hum, I'm also interested if one betatesters could confirm to me when this error will appeared on the bugzilla. thanks in advance.