Re: ESP32-P4 NOR flash LDO voltage
Posted: Mon Nov 10, 2025 5:13 pm
Hi, my boards arrived. 
Putting a jumper between pins 71 and 30 did work: as in, I could power up the board, connect USB Serial/JTAG, burn PXA0_TIEH_SEL_0 to 0b10, and confirm that LDO1 was outputting 1.8V. The jumper could then be closed and firmware could be loaded normally.
However! If the firmware is compiled without disabling CONFIG_ESP_LDO_RESERVE_SPI_NOR_FLASH in menuconfig, it will immediately boot up and put 3.
.3V straight back on LDO1
So, if i ever want to try running an example project on my board and i forget to disable that setting, I will brick it
I see that the official documentation around using the ESP32-P4 with 1.8V flash has changed to reflect the issue with the jumper, and it also seems like there is new documentation in early builds of esptool and espefuse around it.
Is anything different with regards to flash voltage in silicon 1.3 or upcoming revisions?
I'd like to go to mass production with this product and it isn't really feasible to add a hand-soldered jumper halfway through the assembly and test process. Ideally it would just be one "set it and forget it" strapping pin like on the S3.
Putting a jumper between pins 71 and 30 did work: as in, I could power up the board, connect USB Serial/JTAG, burn PXA0_TIEH_SEL_0 to 0b10, and confirm that LDO1 was outputting 1.8V. The jumper could then be closed and firmware could be loaded normally.However! If the firmware is compiled without disabling CONFIG_ESP_LDO_RESERVE_SPI_NOR_FLASH in menuconfig, it will immediately boot up and put 3.
.3V straight back on LDO1
So, if i ever want to try running an example project on my board and i forget to disable that setting, I will brick it
I see that the official documentation around using the ESP32-P4 with 1.8V flash has changed to reflect the issue with the jumper, and it also seems like there is new documentation in early builds of esptool and espefuse around it.
Is anything different with regards to flash voltage in silicon 1.3 or upcoming revisions?
I'd like to go to mass production with this product and it isn't really feasible to add a hand-soldered jumper halfway through the assembly and test process. Ideally it would just be one "set it and forget it" strapping pin like on the S3.