ESP32 Forum

Hi,

Hardware:
Wrover-kit, all jumpers removed, onboard-module flash cleared.
External Wrover module connected to Wrover-kit via the following wires:
3.3V, GND, RXD, TXD, IO0 and EN. There is nothing else connected to the external Wrover module.

If also connecting MTDI, MTDS, MTCK and MTDO, OpenOCD detects the two cores and behaves the same as with the on-board module. (debugging the on-board module works)

Flashing the chip works fine, but on boot I get the following error over and over:

rst:0x10 (RTCWDT_RTC_RESET),boot:0x33 (SPI_FAST_FLASH_BOOT)
flash read err, 1000
ets_main.c 371
ets Jun 8 2016 00:22:57

At first I thought it was the MTDI pin that needed a pull-up/pull-down, but no - the Wrover module already has a pull-up (R9) to set the 1.8V for the SPI flash voltage. In menu config, the VDDSDIO LDO is set to 1.9V.

Anyone got an idea why the module won't boot?

I figured it out - I've got an alias 'maf' to that does 'make app-flash monitor', but as the Wrover module is completely blank it's missing the boot partition. Running 'make flash monitor' once solves it.

Howdy Permal,
Thanks for taking the time to follow up on the puzzle and respond. I've got the feeling that this post will answer that of other users long into the future. For me the key-phrase will be:

flash read err, 1000

Which is likely the message that will be issued when the bootloader isn't found. A nice new piece of knowledge to add to our collective tribal history.