How to mount/access "hassos-boot" partition?

Installation Home Assistant OS
1

On a Raspberry Pi I want to access config.txt in “hassos-boot” partition without shutting down HASS OS, pulling sd card out and accessing it on another system (e. g. Windows client).

How to access the partition using SSH/terminal (maybe a remount with read option)?

2 
ssh root@hassio -p 22222

once inside you get a prompt like ha >
there you type:

login

your prompt will change into #
now you can:

mount /dev/sda1 /mnt/
cd mnt/
vi config.txt

and then reboot. I hope this helps!