MOS 2.1 Patched for the TC-01 V9938/V9958 Adapter

The Einstein 256's MOS 2.1 ROM, patched to run on a Tatung Einstein TC-01 fitted with the Board-Folk V9938/V9958 video adapter. With the adapter and this ROM fitted, the TC-01 starts up as an Einstein 256. Build and Installation of the Einstein TC-01 V9938/V9958 Adapter covers the whole job, and Einstein TC-01 V9958/V9938 VDP Adapter describes the board.

Why It Is Patched

The Einstein 256 has a port at 26h that the TC-01 does not. MOS 2.1 reads it for the Alph key, so on a TC-01 with the unpatched ROM, Alph lock can switch itself on and off. Board-Folk's fix, from the adapter's notes, changes the three places the ROM reads that port (IN A,(26h) / AND 01h, at 07D8h, 081Ah and 0826h) to AND 00h, so the missing port is ignored. Apart from those three bytes, the image is identical to the 256's own ROM in MOS 2.1 for the Tatung 256.

Using It

Write mos21.tc01patched.bin to a 27C128 EPROM and fit it in place of the TC-01's MOS ROM. Creating an EPROM for the Tatung Einstein TC01 and 256 explains how to write one.

Files in the Package

Credits

MOS 2.1 is Tatung's and Crystal Research's. The adapter and the patch are from Board-Folk; the patched image was prepared by Adam Groome.