Inkplate 4 Tempera display frozen after loading sketch

Soldered_Bot · March 16, 2025, 9:02am

Customer:

I have an Inkplate 4 Tempera that ran a few demo programs OK, but when I loaded another, it stopped working. I can access it with Arduino IDE via USB and even load programs, but the display stays exactly the same, with indented and inverse text like this:

Inkplate 4TEMPER

A

How can I unbrick it?

Originally submitted via email support on 16 March 2025. Migrated to the forum for community visibility.

Soldered_Bot · March 17, 2025, 9:12am

Soldered Support:

Check the Serial monitor at 115200 baud to see if something is being written. If it’s an ESP32 exception, you can use the exception decoder: GitHub - me-no-dev/EspExceptionDecoder: Exception Stack Trace Decoder for ESP8266 and ESP32 · GitHub

If not, please re-upload one of the simple Inkplate Tempera examples. It’s likely a software issue rather than a hardware problem.

Soldered_Bot · March 20, 2025, 10:19am

Customer:

I found the issue was caused by errors in the example programs themselves. The Inkplate4_frontlight_mar3a sketch worked OK, but the Inkplate4TEMPERA_Hourly_Weather_Station sketch had problems:

openweathermap.org requires the variable appid and not apiKey to be sent
The Network.cpp file calls the URL:
https://api.openweathermap.org/data/2.5/onecall?lat=%s&lon=%s&appid=%s

whereas it should now be:
https://api.openweathermap.org/data/2.5/weather?lat=%s&lon=%s&appid=%s

After correcting these, the sketch compiled and loaded with a hard reset via RTS pin, but when it ran I got this error on the serial monitor:

Guru Meditation Error: Core 1 panic’ed (LoadProhibited). Exception was unhandled.

Core 1 register dump:

PC : 0x4008c7c9 PS : 0x00060f30 A0 : 0x800d7099 A1 : 0x3ffb1f60
A2 : 0x3ffbdb70 A3 : A4 : 0x000000ff A5 : 0x0000ff00
A6 : 0x00ff0000 A7 : 0xff000000 A8 : A9 : 0x3ffb1f10
A10 : 0x3ffbdb70 A11 : A12 : 0x000007fe A13 :
A14 : A15 : SAR : EXCCAUSE: 0x0000001c

Backtrace: 0x4008c7c6:0x3ffb1f60 0x400d7096:0x3ffb1f70 0x400d3128:0x3ffb2240 0x400e452e:0x3ffb2290

ELF file SHA256: 2f4600b422968e6e

It went into a never-ending rebooting loop. The errors in these sketches are likely what cause apparent “bricking” - the display doesn’t change because the sketch isn’t running properly.

Soldered_Bot · March 26, 2025, 11:11am

Soldered Support:

Glad to hear the device is not defective!

Please use one of the basic examples instead. The open weather sketches are outdated and could cause problems with the API.

Try these:

github.com/SolderedElectronics/Inkplate-Arduino-library

examples/Inkplate4TEMPERA/Advanced/WEB_WiFi/Inkplate4TEMPERA_HTTP_Request/Inkplate4TEMPERA_HTTP_Request.ino

master

/**
 **************************************************
 * @file        Inkplate4TEMPERA_HTTP_Request.ino
 * @brief       Simple HTTP web content fetch example for Soldered Inkplate 4TEMPERA.
 *
 * @details     Demonstrates how to connect Inkplate 4TEMPERA to a WiFi network,
 *              perform a basic HTTP request to retrieve data from the Internet,
 *              and display the received content on the e-paper display.
 *              This example does NOT parse HTML content; it simply prints the
 *              raw HTTP response body on the screen.
 *
 *              The example is intended to demonstrate basic HTTP communication
 *              only - no HTML parsing or content extraction is performed, and
 *              displaying large responses may require text size adjustments.
 *              Expected output is raw text/HTML fetched from the web shown on
 *              the Inkplate display.
 *
 * Requirements:
 * - Board:      Soldered Inkplate 4TEMPERA
 * - Hardware:   Inkplate 4TEMPERA, USB cable

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github.com/SolderedElectronics/Inkplate-Arduino-library

examples/Inkplate4TEMPERA/Advanced/WEB_WiFi/Inkplate4TEMPERA_Show_Pictures_From_Web/Inkplate4TEMPERA_Show_Pictures_From_Web.ino

master

/**
 **************************************************
 * @file        Inkplate4TEMPERA_Show_Pictures_From_Web.ino
 * @brief       Download and display BMP images from the web (Inkplate 4TEMPERA).
 *
 * @details     Demonstrates how to connect Inkplate 4TEMPERA to a WiFi network,
 *              download a BMP image from a web URL (HTTP/HTTPS depending on
 *              the sketch implementation), and render it on the e-paper display
 *              using the Inkplate image drawing functions.
 *
 *              Supported BMP formats are Windows BMP with 1/4/8/24-bit color
 *              depth. Images must fit the display; large images may not render
 *              properly. Make sure the URL points directly to the BMP file (no
 *              HTML redirect pages). Expected output is the downloaded BMP image
 *              shown on the Inkplate screen.
 *
 * Requirements:
 * - Board:      Soldered Inkplate 4TEMPERA
 * - Hardware:   Inkplate 4TEMPERA, USB cable
 * - Extra:      Available WiFi connection

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This way we can verify WiFi works correctly. Fixing the openweather example is something being worked on.