Canon iR4570 Series Service Manual page 959

-Normal Mode (download mode B)
turn on the main power while holding down 1+7; then, make the following selections in service mode:
COPIER>FUNCTION>SYSTEM>DOWNLOAD
-Safe Mode(download mode A)
turn on the main power while holding down 2+8
Use safe mode for the following:
-when you have replaced the HDD.
-when the system fails to start up normally.
The following table shows the functions that may be used in download mode with the SST in use:
Main power
on keypad, 2+8
switch ON
Safe mode
Boot ROM
program
Download mode A
on keypad, 1+7
Boot program
HDD
SYSTEM program
In service mode
COPIER > FUNCTION >
SYSTEM > DOWNLOAD
normal mode
program
Download mode B
F-17-2
Chapter 17
17-3