CC2541: CC2541 SNV write/read abnormal

Hello,

We use CC2541 chip and BLE-CC254x-1.4.2.2.  Enable Large OAD feature.

when we use osal_snv_write/read API，it works abnormal. It can not write succeeded. 

We test the Flash ID from 0x80~0xFE.

So we try to use HAL read/write API.

*************************************

HalFlashErase(page_id); //Flash ID

while( FCTL & 0x80 ); // wait for erase to complete
HalFlashWrite(addr_id, data, data_len);

*************************************

How to use/set  page_id/addr_id/data_len ? 

Thanks

Peter