Messages in this thread | | | Date | Wed, 20 Aug 2003 22:35:24 -0400 | From | Brandon Stewart <> | Subject | Re: usb-storage: how to ruin your hardware(?) |
| |
I think what Matt is saying is that certain functionality of the USB device is soft-coded. So once this data is gone from the device, trying to write to or from it will fail, since the read and write commands are (partially) soft-coded. If this is true, then writing to this device is like trying to ping a computer that was booted up, but had no operating system loaded. It would seem weird to create a device in such a manner, but it is not outside the realm of possibility.
I had a printer (hp lj1000) that operated in exactly this fashion. To work, its firmware needed to be cat'ed to the device before any printing was done. I never got this working and instead just returned the printer and replaced it with a postscript compliant model. I recommend that you do similar. No sense eating the cost. It will be impetus for the manufacturers to make robust and compatible devices.
-Brandon
H.Rosmanith (Kernel Mailing List) wrote:
>-- Start of PGP signed section. > > >>For the vast majority of USB storage devices, it's not possible to kill the >>device like you did. >> >>It looks like the device firmware needs certain data on the first sector to >>operate. The usb-storage communication is working just fine, but the >>device is refusing commands. >> >> > >aha. do you know why the device is refusing commands? it relys on sector0 >to contain some vital information and if this is not there, it refuses >commands? > > > > >>Likely, the unit is unrecoverable unless you can figure out the magic that >>the manufacturer uses to write that beginning few sectors of data. >> >> > >pfhew....I once sent an email to Prolific (manufacturer of this device), but >never got an answer. so, one needs the layout of the first sectors and >a method how to write that ... I wonder if Prolific has this info on their >website ... > > > > >>Matt >> >>P.S. I commonly put ext2/3 filesystems on my CF cards without any >>problems. >> >>P.P.S. The 'strange partition table' you saw probably wasn't a partition >>table at all -- it was likely the start of a VFAT filesystem. I'm guessing >>that if you had just mounted /dev/sda (notice no partition number!), it >>would have worked. >> >> > >I see. the whole flash disk is a single filesystem without partitions >(I used to format HDs this way in the old days :-> > >do you think it is possible to "mke2fs /dev/sda" (once I return the >USB BAR to the vendor and tell them it's "somehow damaged, no idea >why") on a new >
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |