Building MCU firmware

I there any guide for building mcu firmware? With recent problems with calibrations I wanted to modify the code to narrow its origin. From project files I assume it is Keil C51 project. However Lime Microsystems is not available as vendor in default Keil installation. I there any support package available?

Keil project file updated to use Generic/8051(All variants) device, should not need any support packages anymore.
While modifying code be sure not to go above 16384 bytes of const+code memory.

Are you sure? That is 16KB. Datasheet says there is only 8KB.

old chip version had 8KB, latest version has been increased to 16KB. The Datasheet might not have been updated.

That’s good news. That might also explain why I readout different chip mask from register 0x2f.

Can sdcc be used to compile this code?