Fixing a boot loop issue

[heikki.hietala]

Hi all,

I have a lot of ESP32s due to the courses I give at a University of Applied Sciences. However, 4 of them behave rather bad. They do accept upload, but then enter a boot loop with this output:

Code: Select all

rst:0x3 (SW_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0018,len:4
load:0x3fff001c,len:1216
ho 0 tail 12 room 4
load:0x40078000,len:10944
load:0x40080400,len:6388
entry 0x400806b4
ets Jun  8 2016 00:22:57

What I would love to know is, can this be fixed, and if yes, how?

I have found many sites where people issue instrustions on this but none so that I could actually understand how to do it.

All information much appreciated - thank you!

[WiFive]

Are they all the same hardware and same binary? What is a log from a working device? What sdk version was used?

[heikki.hietala]

Yes, they are all DevKitC chips, but they have functioned perfectly well in both Arduino and MicroPython settings. I just started to test my stock, and found these four that fail.

So, all in all, is there a way to get them going again?

[WiFive]

If you are erasing the flash and reflashing a new bootloader and app and they don't work while other identical units do work then I have no suggestions.

[heikki.hietala]

That's what I was afraid of. Oh well, they served well, but my students probably fiddled with the wirings while it was connected.

Or maybe I did.

Thank you for confirming that they cannot be resurrected.

[jglogau]

I have found the same boot loop issue. I know I did
something wrong to get in this state but

You said you had four that were bricked.

Can you say out of how many you have for your labs total?

[heikki.hietala]

Probably 50.