Verify current setting:

# eeprom | grep auto-boot 

Change:

# eeprom auto-boot?=false 

Verify updated setting:

# eeprom | grep auto-boot 

Reset the host:

# init 6

From the OK prompt

ok setenv auto-boot? false

Verify the change:

printenv auto-boot?
auto-boot? =            false

Reset the host:

reset-all