A400 requires a Micro SD card standard U3&Class 10 or above. You can check if the Micro SD card is eligible by its U3 and Class 10 logo.

No, the parking surveillance mode can only be activated after installing the 70mai Hardwire Kit.

We strongly recommend a 70mai hardwire kit to avoid device incompatibility.

Please try
1. using another USB power cable
2. using a different micro SD card.If the A400 still doesn't turn on, please reach out to us at onlinehelp@70mai.com

If you want to record in 2560x1440P, please remember to select 'high compression ratio' in the video storage settings.When this is set to 'low compression ratio', you're only able to record in 1080P.

You can access the A400's online guide via this link