Experimental: Heltec V4 + Expansion Kit V1 on Cairn 127, with the blank-screen fix. Not yet confirmed on a kit. Please tell us what you see.
What experimental builds are. Use MeshCore-HeltecV4KitV1-Cairn127-2026-11-03-full.bin.
Cairn 127 for the Heltec V4 + Expansion Kit V1 -- test build (2026-11-03)
For the Heltec WiFi LoRa 32 V4 (ESP32-S3R2, 2 MB PSRAM, 16 MB flash, SX1262) on the Expansion Kit V1.
Not for the V4-R8 on the Expansion Kit V2: that board has its own build in the Cairn 127 release.
Nothing in it can damage the board, and you can always flash Meshtastic or MeshCore back.
New in this build:
- The blank-screen fix from 126 test 1: the kit's power switch (GPIO 36) held the way Meshtastic and
MeshCore hold it.
- Everything in Cairn 127: blocking a node (long-press it in Nodes), the live page in a browser
(Settings > Wi-Fi > Live page), sharper text, and a lower CPU clock while the screen is on and still.
The Kit V1 is out of the normal release until a kit confirms the screen works, so the online update
on a kit will not offer 127: flash this file by hand.
File: MeshCore-HeltecV4KitV1-Cairn127-2026-11-03-full.bin
FLASH IT (Chrome or Edge on a computer)
1. Open https://espressif.github.io/esptool-js/
2. Plug the V4 in with a USB-C data cable. Click Connect and pick its port.
No port, or it won't connect: hold PRG, press and let go of RST, let go of PRG, then Connect again.
3. Click Erase Flash and wait for it to finish (this clears the other firmware's settings).
4. Flash Address 0x0, the -full.bin above, then Program.
5. When it says done, press Disconnect, then press RST.
WHAT TO TELL US
- Does the screen show a picture now? Does touch work?
- If it is still blank: is the backlight on (the screen glows) or completely dark?
- A boot log helps either way: open a serial monitor at 115200 baud, press RST, and copy the first
60 lines or so.