This article describes the basic flow for EMV fallback using the ID TECH L2 Common Kernel.
Fallback Flow:
Start EVM Transaction, "Is chip readable?"
if yes, proceed with the transaction.
If no look at the magstripe-service code for "Is chip present on the card?"
If yes, EMV_RESULT_CODE_FALLBACK_TO_MSR
if no EMV_RESULT_CODE_SWIPE_NON_ICC
If no magstripe or magstripe is unreadable, EMV_NO_MATCHING_APP