TDA4VM: SDL POK Re-configuration of Trim for Test Purpose Failed

Hi TI Experts,

I am trying to test POK monitoring for our project. Here is my test code:

void SdlPok_Init(void)
{
    int32_t retVal;
    SDL_POK_Inst               instance;
    SDL_POK_config             pPokCfg;

    instance = SDL_POK_VDD_CORE_UV_ID;
    pPokCfg.voltDetMode = SDL_PWRSS_SET_UNDER_VOLTAGE_DET_ENABLE;
    pPokCfg.trim = 127;

    /* Unlock the MMR in order to access the POK registers */
    *((uint32_t *)(SDL_WKUP_CTRL_MMR0_CFG0_BASE + SDL_WKUP_CTRL_MMR_CFG0_LOCK6_KICK0)) = KICK0_UNLOCK_VAL;
    *((uint32_t *)(SDL_WKUP_CTRL_MMR0_CFG0_BASE + SDL_WKUP_CTRL_MMR_CFG0_LOCK6_KICK1)) = KICK1_UNLOCK_VAL;

   retVal = SDL_POK_init(instance, &pPokCfg);
   if(retVal != SDL_PASS)
   {
    while(1)
    {

    }
   }

   /* Pass the expected config */
   retVal = SDL_POK_verifyConfig(instance, &pPokCfg);
    if (retVal != SDL_PASS)
    {
    while(1)
    {

    }
    }

}

I can see the system is not stuck in the infinite loop, hence 

SDL_POK_init() and 

SDL_POK_verifyConfig() returns passed. 

After the test code has been run, I can see that the trim value for POR_VDD_CORE remains unchanged!

Setting of the trim value is failed. Seems the SDL_POK_Init() is not working but returns SDL_PASS.

Then I noticed in thread [FAQ] TDA4VM: Enabling POK Modules - Processors forum - Processors - TI E2E support forums

"The CTRLMMR_WKUP_PRG0_CTRL.POK_EN_SEL bit has a reset value of zero which means POK enablement comes from hardware tie-offs (please reference screenshot below from the TDA4VM TRM).  If the POK is not enabled with hardware tie-offs, the CTRLMMR_WKUP_PRG0_CTRL register could be initialized by software to enable VDDAR_MCU, VDDSHV0_MCU, VDD_MCU, VDDAR_MCU, VDDSHV0_MCU, and VDDA_PMIC_IN POK detections."

And I can see my TDA4, POK_EN_SEL = 0, which means POK enablement comes from hardware tie-offs.

In this case, does it mean that I cannot modify the trim values of POK modules even with SDL POK APIs?

Thanks.