[split] Change password from external media

[James Good]

>onto a micro USB,,, surely you mean micro SD? (uSD)
Is there still a bootable distro on the emmc?  If so, edit password file, /mount-point/etc/shadow (ON EMMC)
You can edit a user password too, if needed
As to wifi, check with ifconfig  OR  ip a  (all this as root or sudo)
because of systemd, the normal command may not work, refuses (wifi) password
nmcli dev wifi con <ap name>  -a    (-a=--ask)
What I had to do (in vt - virtual terminal)
nmcli con up <ap name> -a
If unsure of name,,, nmcli dev wifi list

wdt,
You are right, the card was misidentified by me.  It is a microSDHC card.  As for an earlier distro on the emmc, I am not sure.  In truth, I am almost a rank amateur when it comes to almost anything Linux.  And my knowledge of the inner workings of any other computer language is about the same.  I will keep your suggestions and work with them on the laptop.
Thank you.
James Good