TS-7400/TS-9441 MANUAL
SOFTWARE
3.6 SD flash card security features
Technologic Systems provides a "sdlock" Linux command which can be used to
manipulate SD card hardware-enforced password locks and set the card's permanent
write-protect feature. Using a password protected SD card is a great way to ensure
software security and/or to make sure your TS-7400 based product cannot be used in an
unintended matter once deployed.
$ sdlock
Usage: sdlock [OPTION] ...
Controls SD card lock and permanent write-protect features.
General options:
-p, --password=PASS Use PASS as password
-c, --clear
Remove password lock
-s, --set
Set password lock
-u, --unlock
Unlock temporarily
-e, --erase
Erase entire device (clears password)
-w, --wprot
Enable permanent write protect
-h, --help
This help
When the TS-7400 is configured with the TS-SDBOOT bootup firmware, the SD unlock
password can be stored in onboard EEPROM for automatic unlocking and booting of
password protected SD cards. By default, TS-SDBOOT will still boot unlocked cards, but
this behavior can be changed with the "--verifylock" option to the "tsbootrom-update"
command described above-- with the "--verifylock" option the TS-7400 will only boot
locked SD cards.
TS-SDBOOT can also verify an arbitrary number of sectors of the SD flash card before
allowing bootup. If the stored CRC does not match the actual CRC, the board will refuse
to boot and blink the red LED continuously.
The various SD commands that manipulate the password lock are marked as "optional" in
the SD card specification. This means that not all SD card vendors may implement them
in their devices. If they are not implemented, you will not be able to set the SD lock with
the "sdlock" command.
For further information, contact a Technologic Systems' engineer.
3.7 TS-7400 specific Linux devices
Although working with the TS-7400 Linux is identical in most ways to working with a PC
version Linux, one does need to be aware of some driver differences.
✔
The serial port device nodes are /dev/ttyAM0, /dev/ttyAM1, and /dev/ttyTS0,
respectively. The default PC uses /dev/ttyS* as device names. The software API to
these devices is the same as on the PC.
✔
The onboard flash is broken up into partitions and accessed through the Linux driver
framework known as "MTD", or (M)emory (T)echnology (D)evice. The partitioning is
dynamic and depends on the DOS-style MBR found at sector 0 of the flash. This MBR
can be changed by using the "fdisk" command on the /dev/mtdblock/0 device, but
doing so is not recommended.
/dev/mtdblock/0 - Whole disk block device driver.
/dev/mtdblock/1 - First MBR partition (bootloader kernel binary)
/dev/mtdblock/2 - Second MBR partition (bootloader initrd)
/dev/mtdblock/3 - Third MBR partition (Linux YAFFS2 filesystem)
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