SC143 is a low profile ROM module designed for the RC2014 bus.
This module includes a 128k byte FLASH memory chip which is divided into four 32k byte banks.
It has been designed primarily as an alternative to the Classic II ROM module which is limited to 8k byte banks. The use of 32k byte banks allows larger firmware to be used.
Details of the currently supplied firmware can be found here.
In theory, the FLASH memory can be written to but this requires special software which is not currently available (as far as I know).