Access FD-CAN bootloader from classic CAN transceiver

[kimj]

I'm in situation ​programming STM32L552 (FD-CAN) MCU from classic CAN (CAN 2.0B) transceiver host through CAN communication line. According to AN5405, this kind of bootloader doesn't be compatible with classic CAN. However, for avoiding my hardware change, I am struggling to try make it compatible or find any polyfill. There isn't any solution on this situation?