Question : Problem: How to upgrade firmware of HP Laserjet 4 / 4Plus

How to upgrade firmware of HP Laserjet 4 / 4Plus ?

I had tried to contact HP, but the representative told me the files have been removed from their website.

Any one can help ?

Thanks !

Birdie ^_^

Answer : Problem: How to upgrade firmware of HP Laserjet 4 / 4Plus

You still haven't told us what exact type of memory you had that worked in
an LJ4+ but not in an LJ4...

Per the previous comments, you were most likely trying memory that is
supported in LJ4+ but is not supported in LJ4, and the firmware is probably fine.