Stuck in bootloader

[StefanS]

Hello,

my device is sometimes stuck in the bootloader.
This is the last output that I get

Code: Select all

[2019-01-30 17:34:54] I (12) boot: ESP-IDF v3.1.2-dirty 2nd stage bootloader
[2019-01-30 17:34:54] I (13) boot: compile time 15:34:11
[2019-01-30 17:34:54] I (13) boot: Enabling RNG early entropy source...
[2019-01-30 17:34:54] I (16) boot: SPI Speed      : 40MHz
[2019-01-30 17:34:54] I (21) boot: SPI Mode       : DIO
[2019-01-30 17:34:54] I (25) boot: SPI Flash Size : 4MB
[2019-01-30 17:34:54] I (29) boot: Partition Table:
[2019-01-30 17:34:54] I (32) boot: ## Label            Usage          Type ST Offset   Length
[2019-01-30 17:34:54] I (40) boot:  0 nvs              WiFi data        01 02 00009000 00005000
[2019-01-30 17:34:54] I (47) boot:  1 otadata          OTA data         01 00 0000e000 00002000
[2019-01-30 17:34:54] I (55) boot:  2 ota_0            OTA app          00 10 00010000 001f0000
[2019-01-30 17:34:54] I (62) boot:  3 ota_1            OTA app          00 11 00200000 001f0000
[2019-01-30 17:34:54] I (69) boot: End of partition table
[2019-01-30 17:34:54] I (74) boot: No factory image, trying OTA 0
[2019-01-30 17:34:54] I (78) esp_image: segment 0: paddr=0x00010020 vaddr=0x3f400020 size=0x2ce7c (183932) map
[2019-01-30 17:34:54] I (152) esp_image: segment 1: paddr=0x0003cea4 vaddr=0x3ffc0000 size=0x0316c ( 12652) load
[2019-01-30 17:34:54] I (157) esp_image: segment 2: paddr=0x00040018 vaddr=0x400d0018 size=0xb9ae0 (760544) map
[2019-01-30 17:34:54] I (425) esp_image: segment 3: paddr=0x000f9b00 vaddr=0x3ffc316c size=0x00338 (   824) load
[2019-01-30 17:34:54] I (425) esp_image: segment 4: paddr=0x000f9e40 vaddr=0x3ffc34a4 size=0x00000 (     0) load
[2019-01-30 17:34:54] I (432) esp_image: segment 5: paddr=0x000f9e48 vaddr=0x40080000 size=0x00400 (  1024) load
[2019-01-30 17:34:54] I (441) esp_image: s

It doesn't happen always, maybe once a day if I wakeup every 5 seconds and go to sleep after 1 second of work.
In newer ESP IDFs there is a CONFIG_BOOTLOADER_WDT_ENABLE option that seems to care of this.

Anyone knows why this happens and the solution?

Thank you

[Angus]

Usually this indicates some kind of hardware problem like a power glitch or something going wrong with the crystal. Although it can also indicate a problem with the USB to serial chip (the ESP32 is actually continuing to boot but serial communications have been lost).

What hardware are you using? If it's a custom board, suggest checking the ESP32 Hardware Design Guidelines which can be downloaded from here.

If it's a development board, sometimes bad/glitchy USB cables or USB ports can be enough to cause these kind of problems.

You're correct that the new bootloader WDT option is designed to work around these kind of problems when they occur on the ESP32 side.

[Dazzy369]

I found 2 solutions to the problem which seems to be cause by a small amount of code being regarded as no code by the esp32 so it just stays in boot mode thinking that it has no code to run.

Firstly, holding the boot button on the ESP32 down prior to connecting the USB cable, and then only releasing it once the sketch starts uploading. this solved the problem.

Secondly, this solution only works in Arduino IDE, before uploading the sketch go to the upload options and choose the "large app" option