(Original log)
process_usb_msg(), payload: ff ff ff ff ff 90 00 00 a4 08 04 04 a4 7f ff 6f 07 61 1e 00 c0 00 00 1e c0 62 1c 82 02 41 21 83 02 6f 07 a5 03 da 01 02 8a 01 05 8b 03 6f 06 05 80 02 00 09 88 01 38 90 00 00 a4 08 04 04 a4 7f ff 6f 32 61 1d 00 c0 00 00 1d c0 62 1b 82 02 41 21 83 02 6f 32 a5 03 da 01 02 8a 01 05 8b 03 6f 06 05 80 02 01 2c 88 00 90 00 00 b0 00 00 00 b0 ff ff ff ff ff ff ff ff ff ff ff ff 
APDU: 00 b0 00 00 10 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 90 00 
APDU: 00 a4 08 04 04 7f ff 6f 07 61 1e 
APDU: 00 c0 00 00 1e 62 1c 82 02 41 21 83 02 6f 07 a5 03 da 01 02 8a 01 05 8b 03 6f 06 05 80 02 00 09 88 01 38 90 00 
APDU: 00 a4 08 04 04 7f ff 6f 32 61 1d 
APDU: 00 c0 00 00 1d 62 1b 82 02 41 21 83 02 6f 32 a5 03 da 01 02 8a 01 05 8b 03 6f 06 05 80 02 01 2c 88 00 90 00 
process_usb_msg(), payload: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 
process_usb_msg(), payload: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 90 00 00 a4 
process_usb_msg(), payload: 00 04 02 a4 6f 40 61 20 00 c0 00 00 20 c0 62 1e 82 05 42 21 00 18 05 83 02 6f 40 a5 03 da 01 02 8a 01 05 8b 03 6f 06 06 80 02 00 78 88 00 90 00 00 a4 00 04 02 a4 6f 3b 61 20 00 c0 00 00 20 c0 62 1e 82 05 42 21 00 22 64 83 02 6f 3b a5 03 da 01 02 8a 01 05 8b 03 6f 06 07 80 02 0d 48 88 00 90 00 00 a4 00 04 02 a4 6f 49 61 20 00 c0 00 00 20 c0 62 1e 82 05 42 21 00 22 0a 83 


(with my comments)
process_usb_msg(), payload: ff ff ff ff ff 90 00 00 a4 08 04 04 a4 7f ff 6f 07 61 1e 00 c0 00 00 1e c0 62 1c 82 02 41 21 83 02 6f 07 a5 03 da 01 02 8a 01 05 8b 03 6f 06 05 80 02 00 09 88 01 38 90 00 00 a4 08 04 04 a4 7f ff 6f 32 61 1d 00 c0 00 00 1d c0 62 1b 82 02 41 21 83 02 6f 32 a5 03 da 01 02 8a 01 05 8b 03 6f 06 05 80 02 01 2c 88 00 90 00
(from the command output available above)
APDU: 00 b0 00 00 10 -> ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff SW:90 00 
APDU: 00 a4 08 04 04 7f ff 6f 07 -> SW:61 1e 
APDU: 00 c0 00 00 1e -> 62 1c 82 02 41 21 83 02 6f 07 a5 03 da 01 02 8a 01 05 8b 03 6f 06 05 80 02 00 09 88 01 38 SW:90 00 
APDU: 00 a4 08 04 04 7f ff 6f 32 -> SW:61 1d 
APDU: 00 c0 00 00 1d -> 62 1b 82 02 41 21 83 02 6f 32 a5 03 da 01 02 8a 01 05 8b 03 6f 06 05 80 02 01 2c 88 00 SW:90 00 

(simtrace apdu_split stops here, follows manual parsing with comments)
This is not parsed any more: (Le 00 == "anything, up to 256" with case 2 APDU-s)
APDU: 00 b0 00 00 00 -> b0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff SW:90 00 
APDU: 00 a4 00 04 02 a4 6f 40 SW:61 20 # Le = 40, response is 20
APDU: 00 c0 00 00 20 -> c0 62 1e 82 05 42 21 00 18 05 83 02 6f 40 a5 03 da 01 02 8a 01 05 8b 03 6f 06 06 80 02 00 78 88 00 SW:90 00
APDU: 00 a4 00 04 02 a4 6f 3b SW:61 20 # Le = 3b, response is 20
APDU: 00 c0 00 00 20 -> c0 62 1e 82 05 42 21 00 22 64 83 02 6f 3b a5 03 da 01 02 8a 01 05 8b 03 6f 06 07 80 02 0d 48 88 00 SW:90 00
APDU: 00 a4 00 04 02 a4 6f 49 SW:61 20 # Le = 49, response is 20
APDU: 00 c0 00 00 20 -> c0 62 1e 82 05 42 21 00 22 0a 83 ...