Hi,
Neither of your download requests were received properly as signified by the TX_FAILED message.
[A4][09][50][00][44][09][00][00][00][00][00][00][B0][00][00] // Download Request p1
[A4][09][4E][00][43][2C][02][00][00][00][00][00][8E] // Transport state
[A4][03][40][00][01][0A][EC] // TX_START
[A4][09][50][A0][00][01][00][00][FF][FF][00][00][5C][00][00] // Download Request p2
[A4][03][40][00][01][06][E0] // TX_FAILED
[A4][03][40][00][50][20][97] // TRANSFER_SEQUENCE_NUMBER_ERROR
You cannot wait for TX_START before you send your second packet, burst packets must be sent consecutively to ANT, otherwise the buffer will starve.
Cheers