No, the only way a CDMA 4S will work on a GSM carrier abroad is if the CDMA carrier it's locked to "unlocks" the GSM slot for such use. As you've stated it has a bad ESN... so I don't see that happening. However, there is light at the end of the tunnel. You can use a Gevey Ultra S sim interposer to unlock the GSM sim slot for use w/ any sim card... domestic and abroad. Check them out at ApplenBerry.com... the only supplier we recommend getting Gevey products from. Because frankly... 90% of the Gevey's you come across online or in cell shops are FAKE!