Need to erase efuse bits

[anirudhsayee]

We are using ESP32D2WD chip and i have flashed my boards with arduino ide and later i found out that the pins used by arduino for external flash and psram are not matching with the pins of our schematic. So we want to change our pins as per our schematic. I have gone through some links and found out that espefuse is providing that provision for changing pins of accessing flash. I have got the fuses summary from the chip.
I have attached the efuse summary,i have to change SPI_PAD_CONFIG_Q (BLOCK0) from 17 to 7. I know that efuse bits cannot be changed from 1 -> 0. But still i want a way to change the pins because, we have to change chips in all our PCB's if we can't change the pins.
I have attached the efuse summary also.

Thanks in advance.

[WiFive]

You can't do it but you may be able to boot a custom bootloader from internal flash that will change to external flash then load the app. However two problems:
1. d2wd internal flash runs at 1.8v so your external flash and psram should also be 1.8v
2. The external flash and internal flash should have different cs pins

Why are you using d2wd instead of d0wd? All d2wd will come from the factory with these efuse settings.

[anirudhsayee]

Extremely thanks for the reply, I have a doubt that if i use external flash and PSRAM which are working on +3.3V and pull MTDI pin to low, for setting VDD_SDIO to +3.3V, will it work for ESPD2?, i am not seeing in the datasheet that if we pull MTDI line to low VDD_SDIO is set to +3.3V but i don't know that this will set the SPI bus voltage levels to +3.3V.

Regarding selection of D2, we are new to esp32 so we have tried with our first version.