====== Special modes ======
By holding special key combinations pressed during power-on of the unit you can enter certain special modes.

===== Lifeboat mode =====
If you keep the **ALT** button pressed while turning the power on the unit will start in [[troubleshooting:lifeboat]] mode.

===== Factory defaults =====
If you keep **SEL** and **ALT** buttons pressed while turning the power on a reset to [[settings_and_administration:factory defaults]] is performed, and unit enters [[troubleshooting:lifeboat]] mode.

===== Safe mode =====
If you keep the **SET** button pressed while turning the power on, and keep it pressed until "SAFE" is shown in display, Internet Gate is started in [[troubleshooting:safe mode]], temporarily using factory default values.

===== Time machine mode =====
^ :!: Only dual-banked models support time-machine mode ^
| To see if your unit does support time-machine mode check the [[web GUI:device information]] page. In the Hardware, Flash ID field it must say "8+8MB" to indicate a dual-banked flash supporting time-machine mode.\\ If Hardware, Flash ID only lists 4MB or 8MB then your unit is not dual-banked and time machine mode is not supported. |

If you keep the **SEL** button pressed while turning the power on, and keep it pressed unit "OLd" is shown in display, the unit is started using previous firmware and settings used before last upgrade.

Time machine mode works in the following way:\\ 
Assume you had release 5.40 in your unit before, but have upgraded to release 5.50 since. Using the time machine you can temporarily revert back to the previous release 5.40 and the configuration you once had before you upgraded. Your unit will be restored to how it was before the upgrade.

The effects are only temporary - powering the unit off and on again will result in a normal boot to current release and configuration again.

Time machine can **not** be used if:
  * Your unit have never been upgraded (thus there is no older firmware)
  * The last upgrade has been aborted or failed
  * Your unit has is not dual-banked (see above)
  * You use a firmware release older than 5.33

==== Advanced ====
The state of the SEL button is sampled twice during boot: once about 5 seconds after power-on and once about when CFG and RST are lit during the power-on process. The first sample decides what firmware to use, the second what configuration to use:
^ RST ^ CFG RST ^ result ^
|  -  |  -  | normal boot |
|  -  |  SEL  | new firmware, old configuration |
|  SEL  |  -  | old firmware, new configuration |
|  SEL  |  SEL  | old firmware, old configuration |
Thus for example if you hold SEL button pressed when turning the unit on, but release it after about 10 seconds, before CFG RST is lit, the unit will start using the old firmware that was used before the last upgrade, but your current configuration.