have added your asked to 1.9k, I attached below. I didn't find the datasheet of M29W128G. It seems no need to add specific parameter to code if this is a new part and it is compliance to CFI standard. From 1.8, brjtag can work well with CFI compatible flash.
I plan release 1.9 source code when usb type cable using stablely. Also have to add some comments and clean up obsolete code for usb parts.