Will the Keil ULINK2 work with the 8051 processor NXP P80C32SBPN? Concern is the 8051 is an old microprocessor and doesn't support a lot of the debug features of newer processors (eg. JTAG).
Then, surely, you must be thoroughly familiar with its capabilies by now...?!
"hoping to save some time when customizing/updating software"
How about taking something like an SiLabs chip (with on-board debug), making a little plug-in module, and using that - with all its visibility, debugability, etc - during your "customizing/updating"?
That would be, literally, an in-circuit emulator!
There'd be a bit of a learning curve as you find what's transferrable, and what really has to be done on the real target - but I'd think there should be a worthwhile benefit to be had?
PS
Are you still able to get reliable supplies of them?