You can shift gears down by operating the selector lever or the steering shift switches (some models).
M6
→ M5
→ M4
→ M3
→ M2
→ M1
Using selector lever
To shift down to a lower gear, tap the selector lever forward (-)
once.

Using steering shift switch (Some models)
To shift down to a lower gear with the steering shift switches, pull the DOWN switch (-
) toward you once with your fingers.

WARNING
Do not use engine braking on slippery road surfaces or at high speeds:
Shifting down while driving on wet, snowy, or frozen roads, or while driving at high speeds causes sudden engine braking, which is dangerous. The sudden change in tire speed could cause the tires to skid. This could lead to loss of vehicle control and an accident.
Keep your hands on the steering wheel rim when using fingers on the steering shift switches:
Putting your hands inside the rim of the steering wheel when using the steering shift switches is dangerous. If the driver's air bag were to deploy in a collision, your hands could be impacted causing injury.
NOTE
Manually Shifting Up
Second Gear Fixed ModeMazda 6 Owners Manual: Air bag module and pre-tensioner seat belt disposal procedures
Warning
Before scrapping a vehicle with a live (undeployed) air bag module
and pre-tensioner seat belt, deploy the air bag module and pre-tensioner
seat belt. Never dispose of a live (undeployed) air bag module and pre-tensioner
seat belt.
The air bag module and the pre-tensioner seat ...
Mazda 6 Owners Manual: Rear door speaker removal/installation
1. Disconnect the negative battery cable.
2. Remove the rear door trim.
3. Remove in the order indicated in the table.
4. Install in the reverse order of removal.
Rear Door Speaker Installation Note
Attach the speaker with the wiring harness placed in the groove of the door
unit panel.
...