WRAM should be randomized at start but that isn't the problem with this game. It's a mapping issue. Banks $F0-$FF are overwritten with SRAM but Tokimeki Memorial and Wizardry Gaiden are pretty big and have ROM mapped there.
so we finally have found an example where lines 135-136 of snescart.c apply:
/* There could be some larger image needing banks 0x70 to 0x7f at address 0x8000 for ROM
* mirroring. These should be treated separately or data would be overwritten by SRAM */
great! I was waiting for that since forever!!!!