To edit files on a raspberry pi when you are unable to mount ext4 disks, it is possible to enable SSH over USB.
This is also useful if you do not have any peripherals you can attach to the pi.
If however you are running linux you can directly edit /etc/wpa_supplicant/wpa_supplicant.conf
, etc/network/interfaces
and
/etc/dhcpcd.conf
.
There was a security update to the Raspian images.
To enable ssh you need to put a blank ssh
file in the boot directory.