Internal flash memory operations when softdevice present

Question

Hi everyone, 
 First, my current environment is SDK 17.1, s332 v7.0.1 and nrf52832. 
 We recently have migrated from SDK 14 and we are still facing some problems, we have some doubts about how work with the internal flash memory of Nordic. Our current layout is: 
 
 Bootloader: [ROM] 0x71000- 0xD000 [RAM] 0x20002C00- 0xD380 
 Main application: [ROM]0x30000 - 0x1B000 [RAM] 0x20002F70- 0xD090 
 
 And we are using one page memory from internal configuration, starting on 0x70000. The problem comes when we try to erase a page after the first booting. 
 
 We start the application 
 We write some data above 0x70000. 
 We switch off the unit. 
 We start again the unit. 
 We read what we wrote, and check that it is the same. 
 We erase a page - > Not possible. 
 
 We are using the following function sd_flash_page_erase, we also have tried fstorage module, but it does not work for us neither. We saw that it is some flash protection on secure bootloader side, we have tried to disable every protection, but it continues without working. 
 Any idea o recommendation? 
 Is there any flash protection that we should know? 
 Which is the better approach from writing into the internal flash memory when you are using secure bootloader, main app and Softdevice? 
 We will experience some BLE connectivity problems due to the flash operations timing? 
 Thank you very much, 
 Javier

tesc · Accepted Answer

Hi, 
 Based on the bootloader start address of 0x71000 it looks like you have a custom bootloader. The default bootloader placement is at 0x78000. Might there be some wrong settings for bootloader start address? For instance, the bootloader start address should be found in UICR, in the NRFFW[0] register , which can be read at memory address 0x10001014. 
 In addition to triggering an event, sd_flash_page_erase() should give a return value when you call it. Sometimes you might get an error value (different than NRF_SUCCESS which is 0) when calling this function. In that case, you will not get any event either (since the error return value signals that the erase could not be scheduled.) You might also, if the erase was successfully scheduled, get an NRF_EVT_FLASH_OPERATION_ERROR which you should look for. Even if the operation is correctly scheduled, things might happen that means it fails. 
 What return value do you get from sd_flash_page_erase(), and are you getting any NRF_EVT_FLASH_OPERATION_ERROR events? 
 Regards, Terje

Internal flash memory operations when softdevice present

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