The first HP 12c Platinum version (F2231A) did not have parentheses, which often led to awkward key sequences to solve problems in algebraic mode. Since 2005, newer versions (F2232A) of the HP 12c Platinum have parentheses on the blue-shifted functions of the STO and RCL keys. They also support undo and backspace and provide memory for up to 80 CFj registers. The firmware changes increased the ROM size beyond the capabilities of the original processor, so it was replaced by the Generalplus GPLB31A (still with 6502 core), which is also faster. It was manufactured by Kinpo Electronics.