How to disable dynamic security or download old firmware for deskjet?

[PrivateMan]

Added coloured ink to 4121 after using only black for some time and inadvertently updated firmware in the process. Prints yellow and cyan, but not magenta. Never had a problem before. Thought the printer was faulty and bought a newer demo 4123 dirt cheap but without starter modules. Got it to recognise non-HP cartridges for setup, but same identical issue occurs even with a different/new, but still non-HP, ink cartridge. After much time wasted and unnecessary frustration, I concluded the issue is with the dynamic security 'feature'. Now I want to turn that off or downgrade the firmware to a version that doesn't prevent my use of the printers for intended purpose.

Please advise:
a) How to disable dynamic security, and

b) whereto obtain firmware that doesn't prevent me using my printer for intended purpose

[Raj_05]

Hi @PrivateMan,

Welcome to the HP support community.

Thank you for posting your query, I will be glad to help you.  

Please help us with the Printer serial number or the product number on a private message for further assistance.

Here is the link to find the product number:- Click here

In order to access your private messages, click the private message icon on the upper right corner of your HP Support Community profile, next to your profile Name.

Alden4
HP Support