Troubleshooting

Can't connect to SpojBoard-XXXX network

• Password is case-sensitive and shown on the display
• Try forgetting the network and reconnecting
• Move closer to the device
• Disable mobile data on your phone
• Try a different device (laptop vs phone)

Device keeps going to AP mode

• Double-check WiFi password in configuration
• SpojBoard only supports 2.4GHz (not 5GHz)
• Check if router has MAC filtering or client isolation enabled
• Verify WiFi network is broadcasting SSID

API Error: HTTP 401 (Prague only)

Invalid or missing Golemio API key.

• Verify key at api.golemio.cz/api-keys
• Generate a new key if expired
• Check for extra spaces when entering the key
• Note: Berlin (BVG) does not require an API key

API Error: HTTP 429 (Prague only)

Too many API requests (rate limiting).

• Increase refresh interval to 60+ seconds
• Reduce number of stops queried
• Wait a few minutes before trying again
• Check if multiple devices use the same API key

No departures displayed

• Wrong Stop ID:
  • Prague: Verify at data.pid.cz/stops (GTFS ID like "U693Z2P")
  • Berlin: Verify at v6.bvg.transport.rest (numeric ID like "900013102")
• Wrong city selected: Prague IDs won't work with Berlin setting (and vice versa)
• No service: Some stops have no service at night
• Filter too strict: Try reducing minimum departure time to 0
• Test display: Use demo mode to verify hardware works

Display is blank or very dim

• Check the panel arrangement on the Hardware tab matches the panels you attached — two of the three options are 128×64, so pixel size alone cannot tell you which is right
• Try a different panel driver chip on the Hardware tab; some panels stay blank until they get an FM6126A/ICN2038S-style init
• Verify power supply provides at least 5V 2A
• Check brightness setting (0-255, default 90)
• Verify HUB75 cable is properly seated
• Check if panels are receiving power (indicator LEDs on back)

Garbled text, scrambled or half-lit display

• Check the panel arrangement first — picking the 2×2 grid when you have two chained panels (or the reverse) scrambles the image. Change it and reboot; nothing is damaged
• On 64-high panels, confirm the E address line is wired. Without it the top and bottom halves show identical content
• Check HUB75 cable connections between panels
• Verify both panels are powered properly
• Check panel chain order (first panel closest to controller)
• Interleaved or shredded rows specifically can mean a non-standard 1/16-scan "outdoor" panel, which this firmware does not yet remap

Wrong colors

This is a setting, not a wiring fault — do not unplug anything. Open Hardware → Test pattern, which draws three bars labelled R, G and B. If a letter sits on the wrong colour, change the RGB channel order to match what you see and reboot. There are only six permutations and the test pattern identifies the right one immediately.

Colours wrong on only the top or bottom half are the other setting's job: use the custom pin map to swap those two GPIO values. Both live on the Hardware tab, which also works in setup (AP) mode.

Flickering

• Ensure common ground between ESP32 and panel
• Power supply may be insufficient — try 5V 3A
• Check for loose solder joints on connectors
• Check HUB75 cable connections

"Updates not available in AP mode"

Firmware updates are disabled in AP mode for security.

• Connect device to your WiFi network first
• Once connected, updates will be available

"Download failed" or "Installation failed"

• Check internet connection
• Retry — download may have been interrupted
• Verify router allows HTTPS to github.com
• Firmware includes MD5 validation — corrupted files are rejected automatically

"GitHub API error" or "Rate limit exceeded"

GitHub limits unauthenticated requests to 60/hour per IP.

• Wait an hour and try again
• This is normal — not a device issue