STS3215 Run sync_read_write_script on 2 serialized servos failed

[wzds2015]

As titled, groupSyncRead always failed for 2 servos. groupSyncWrite seems to be working. For one servo, it can read position correctly. The error for groupSyncRead is below,

[TxRxResult] Incorrect status packet!
[ID:001] groupSyncRead getdata failed
[ID:002] groupSyncRead getdata failed
[ID:001] GoalPos:100 PresPos:000 PresSpd:000 [ID:002] GoalPos:100 PresPos:000 PresSpd:000

I found default rxPacket only read 5 numbers: [255, 96, 24, 251, 239]. So I relaxed the function "setPacketTimeout" by adding 200ms to the return. By doing this, I can read 6 numbers in rxPacket: [255, 255, 1, 4, 0, 103].

However, these 6 numbers are still not correct. I am facing checksum not correct error: COMM_RX_CORRUPT.

Board: Bus Servo Adapter (A) Wavesahre, DC 9-12.6V
Servo: Feetech STS3215