TPS25750: I2Cw

Hi, 

I am trying to use the TPS25750 I2C pass through to write a register on the BQ25792. 

I am sending the following commands: 

1) Load the DATA1 register

PD address | DATA1 register | #byte count | BQ address | BQ register | BQ #read bytes eg:

0x21            | 0x09                  | 0x03           | 0x6B            | 0x12            | 0x10

2) Load the CMD1 register with "I2Cw"

PD address | CMD1 register | #byte count | 'I' | '2' | 'C' | 'w'

0x21            | 0x08                 | 0x04          | 0x49 | 0x32 | 0x43 | 0x77 

Using a scope, the data being written on I2Cm is (hex):

6B 00 00 00 00 00 00 00 00       00 00 00 00 00 00 00 00 0C 0C. I expect 6B 12 10. 

The task return code is 0x04, which states "Task rejected because the Rx Buffer was locked. This is for Tasks that would require
the PD controller to use the Rx Buffer"

I could not find any reference to the unlocking the Rx buffer. 

Thanks for your help!