Hi attaboyu and henry Thanks so much for your kindly help! I try it , and meet some problem: the bluez-utils/tools/example.psr seems not comply with my chip, so I write another one as: // PSKEY_ANA_FREQ &01fe = 0FA0 // PSKEY_UART_BAUD_RATE &01be = 0EBF I try with the csr's demo before , if it set this two pskey , the chip can work well. And then after hciconfig hci0 up I use bccmd -t hci psload -r csr.psr the two key is write successfully , but then the chip continue to receive messages , seems something wrong. Can you send me your psr file to have a reference , or you can point out anything wrong in my process ? By the way, if I want to read a pskey, how can I do ? I remove the debug message so that you can see the log more clear: ~ # ~ # bccmd -t hci psload csr.psr Loading PSKEY_ANA_FREQ ... done Loading PSKEY_UART_BAUDRATE ... done _________________________________________________ if I using -r in psload the result is : ~ # bccmd -t hci psload -r csr.psr Loading PSKEY_ANA_FREQ ... done Loading PSKEY_UART_BAUDRATE ... done ~ # ~ # bcsp_recv: Error in BCSP hdr checksum both one could not work for hcitool scan: ~ # hcitool -i hci0 scan Scanning ... Inquiry failed: Connection timed out seems after warm reset the connection is bad. So , I wonder, when using hciattach the baudrate is set to 115200 but after the uart_baudrate is set, the baudrate is set to 921600 then how can the hci interface work anymore ? since it is set to 115200, and I can not use bccmd to set the pskey before hciattach is done. I did need to change the baudrate, for this case , how can I achieve it ? Raymond