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