Experimental: first build for the LilyGO T5 E-Paper S3 Pro (H752-01). Tested on one board. Please send a log.
What's in it: Cairn's own interface on the 4.7" 960x540 touch e-paper, made for paper: black on white, solid type everywhere (white labels on black buttons too), and only the changed pixels redrawn so pages switch without flashing. Portrait or landscape, a sleep page with the time, messages and battery, the front light, GPS and microSD maps. Issue #22.
What experimental builds are. Use MeshCore-T5EpaperPro-Cairn126-2026-11-01-full.bin.
Cairn 126 for the LilyGO T5 E-Paper S3 Pro (H752-01) -- first test build (2026-11-01)
The first Cairn build for the T5 E-Paper S3 Pro: the 4.7" touch e-paper with LoRa, GPS and microSD. It has
run on one Pro on the bench (an SX1262 and a Quectel L76K GPS). Nothing in it can damage the board, and you
can always flash LilyGO's firmware back. The older T5 4.7" (H752, no "Pro") is a different board: this
build is not for it.
File: MeshCore-T5EpaperPro-Cairn126-2026-11-01-full.bin
FLASH IT (Chrome or Edge on a computer)
1. Open https://espressif.github.io/esptool-js/
2. Plug the T5 in with a USB-C data cable. Click Connect and pick its port.
No port, or it won't connect: hold BOOT, press and let go of RST, let go of BOOT, then Connect again.
3. Flash Address 0x0, the -full.bin, then Program.
4. When it says done, press Disconnect, then press RST.
The first start clears the glass with a few flashes; after that, pages change without flashing.
THE CONTROLS
Touch everything. Swipe down from the top edge: the quick panel.
BOOT tap: lock and put the screen away. Hold: "Power off?". Unlock: press BOOT twice.
Side key click: screen off. Hold: lock. Double-press: unlock.
PWR turns the T5 on after a power off.
Quick panel Rotate: portrait or landscape. Clean: one flash to clear any traces on the glass.
The slider: the front light (all the way left is off).
WHAT TO TRY (with the console open: Connect in esptool-js, then the Console tab, 115200 baud; press RST
so the log starts from power-up)
1. Is all the text solid and easy to read, black on white, white on the black buttons too? A photo helps.
2. Rotate from the quick panel, both ways. Do taps land where you touch in both?
3. Switch pages for a while, and sit on one for a few minutes. Any grey traces of the last page?
4. Let the screen go dark (or tap BOOT). Does it show the sleep page (time, messages, battery), and does
the time move on each minute?
5. Radio: send a message to another MeshCore node, and have it send one back.
6. GPS: outside, Settings > GNSS > GPS, on. Does it get a fix (a few minutes the first time)?
7. microSD card (FAT32) with Cairn maps: Settings > Hardware > Storage, then the Map tab. How do the
maps look?
8. Battery: is the percentage about right? Plug and unplug USB: does it show Charging and go back?
9. Battery saver: Settings > Hardware > Display > Battery saver on, Bluetooth off, USB unplugged. Leave it
dark for 10 minutes, then tap the screen or press BOOT: does it wake at once?
10. Power off: on battery, hold BOOT, choose Power off. Does the screen say "Powered off"? Press PWR for a
second: does it come back?
11. Copy everything in the console and send it (a GitHub issue, Bug report, with the build's tag),
saying what happened at each step. "It works" is a useful report too.
GOOD TO KNOW
The GPS shares the radio's power and has no standby, so "GPS off" only stops reading it. Online
updates come when the T5 joins the main release; until then, flash the next test build by hand.