How to delete/overwrite the logging memory

we use a MetaWear C to analyse the movement of objects.
The sensor shall log Acc/Gyro data with high data rate until a GPIO interrupt happens.
Then the data shall be downloaded to a Win10 laptop with the MetaWear App.
The Win10-App is created based on your tutorial.

The idea was: if no interrupt happens the newest sensor data would overwrite the oldes data in a kind of ring buffer.
On occurance of the GPIO event, I can download and analyse the last 2 seconds of the movement.

But from other discussions in the forum I learned: it's a flash which cannot be used as ring buffer. The deletion would take time and power.

Next idea was to make movements for 2 seconds, check for the GPIO event, (download), erase the flash, go on for next 2 seconds.
--> But how can I erase the logging buffer of the flash by a SW call?

Thanks for help.
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