Pixhawk 2.4.8 altitude oscillation, other issues

i have a pixhawk 2.4.8 on a tarot 690s hexacopter. I have it flying stable but it likes to oscillate wildly in altitude and when i put it in land mode it continues to do so until it crashes, also i cant figure out how to upload flight logs from it, it always tells me that its the wrong file type.

Hi,sharing with you the site where you can analize your logs: Flight Review, just uploan your log using the button, also filling the spaces is not necessary,so you can skip that.

In order to download the logs,press the button ‘analize tools’ (check the 2 screen) and after (check the 1 screen) press ‘refresh’. Now you should be able to download your logs.

Regarding your first question, now it’s a bit complicated to answer without the logs,but as soon as you provide them,I will try to help as well.