Upgrading software using xmodem, Upgrading software using xmodem 56 – 3Com 3C16895 User Manual

Page 56

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56

C

HAPTER

4: M

AINTAINING

S

OFTWARE

Assert at file: 'vfs_flsh.c', Line: 4549

There are 3 files in this package

SRPU app file error! backup boot file is corrupted!

Select a file to boot from!

the num is 1

the num is 2

File SW7750-V300RE-8016.app is selected for autoBoot:

backup file is SW7750-V300RE-8016.app

There are 3 files in this package

SRPU app file <<FAB64R.app>> is...OK

Decompress

Image...............................................................

....................................................................

....................................................................

....................................................................

........................................OK!

Starting at 0x60000...

The primary image name is saved in flash memory, the secondary image name is
saved in the EPPROM. However, if you use the display boot command to display
the boot image it will only read from flash so only the primary image will be
displayed. The secondary boot image name cannot be displayed when there is an
image error.

Upgrading Software

Using Xmodem

The Xmodem protocol transmits files through serial ports and supports both
128-byte and 1K-byte packets. Xmodem also supports two types of check; normal
checksum and CRC. When there is a packet error, retransmission is supported,
normally 10 times.

The Xmodem protocol completes transmission by receiving and sending programs.
The receiving program first sends the negotiating characters to negotiate the
check means. After passing the negotiation, the sending program begins to send
the packet.

The receiving program checks the packet according to the negotiated means after
receiving a complete packet. The acknowledgement characters are sent after
passing the check and then the sending program continues to send the next

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