Troubleshooting
This section is dedicated to assisting developers in resolving issues encountered while working with the SidecarTridge Multi-device board. It includes common troubleshooting steps, frequently asked questions, and resources for additional support, enabling developers to find solutions and get back to development swiftly.
Table of contents
Common Issues and Resolutions
I cannot stress enough how important it is to clean the cartridge connectors on the Atari ST, not only on the Multi-device. The vast majority of issues encountered are related to dirt, flux or poor connectivity due to rust on the connectors.
Board is detected by the computer but it randomly crashes with different error messages
If your computer randomly crashes with different error messages when the Multi-device is connected, it is likely that the Multi-device is not properly connected to the computer. Please check the following:
- The Multi-device board is properly connected to the Pico W headers.
- The Multi-device board is properly connected to the computer cartridge connector. Please verify that the board is properly inserted and aligned with the cartridge connector.
- The Multi-device board is properly powered. Please verify that the power supply of your computer is working properly. A faulty power supply can cause random crashes and errors.
- The Multi-device board is cartridge connector is clean. Please clean the cartridge connector with isopropyl alcohol.
- The computer cartridge interface is dirty or rusty.
Board is not detected by the computer
If the Multi-device board is not detected by the computer, please check the following:
- Connect the Pico WH to your PC/Mac/Linux using a USB data cable. Observe if the green LED blinks during boot-up. If it doesn’t, the issue could be with the Pico W.
- If the LED blinks upon booting, next connect the Pico W to the Multi-device headers and perform the same operation. The green LED should blink in this case too. If it doesn’t, there might be a short circuit on the Multi-device board.
- Lastly, try connecting the Multi-device to the computer. It is highly recommended cleaning the Multi-device cartridge connector with isopropyl alcohol before doing this. If the LED does not blink in this case, there might be a short circuit on the Multi-device board. If the LED blinks, the Multi-device board is working fine and the issue is with the cartridge connector on the computer.
microSD card not detected
If the microSD card is not detected, please check the following:
- To use the Multi-device effectively, your microSD card needs to be formatted in FAT32 or exFAT. We strongly recommend using a high-quality SDHC, SDXC or SDUC microSD from a reputable brand to ensure optimal performance and reliability. To format the microSD card, you can use the SD Card Formatter tool available for PC/Mac/Linux.
- Check that the microSD card is properly inserted in the microSD card slot. The microSD card should be inserted with the label facing up. The microSD card should be inserted until it clicks.
- Do not power on the Multi-device until the microSD card is properly inserted. If the microSD card is not properly inserted, the Multi-device will not be able to detect it.
- In the Booster app, information about the microSD card is displayed at the bottom of the screen with the space available and the number of files in the folders. If the information is not displayed, the Multi-device is not able to detect the microSD card.
Network issues
The booster app tries to reconnect to the WiFi network continuously
If the booster app tries to reconnect to the WiFi network continuously, please check the following:
- You have entered the correct SSID and password in the configurator. Please follow the instructions in the Initial Factory Configuration section.
- Your WiFi network does not have any MAC address filtering enabled.
- Your network is using a 2.4 GHz band. The Multi-device does not support 5 GHz networks.
- Your WiFi signal is strong enough. If the signal is weak, the Multi-device may have trouble connecting to the network. Try moving the computer closer to the WiFi router or access point.
Can’t connect to the sidecart.local web server
Some networks do not support mDNS, which is used by the Multi-device to resolve the sidecart.local address. If you cannot connect to the sidecart.local web server, please try connecting to the Multi-device using its IP address. You can find the IP address of the Multi-device in the Booster app screen in your Atari ST.
Microfirmware download issues
Error 11 (Booster v2.2.0+) / error 14 (older firmware) when downloading a microfirmware
The Booster app shows “Downloading…”, appears to finish, but then raises error 11 (on Booster v2.2.0 and later) or error 14 (on Booster firmware older than v2.2.0), and the microfirmware never becomes available in the Apps tab. The Multi-device is online, yet the local /apps cache on the microSD card is incomplete or corrupted.
Both numbers refer to the same condition in the firmware: the DOWNLOAD_MD5MISMATCH_ERROR value of the internal download_err_t enum was renumbered when other error codes were added in v2.2.0, so the user-visible number changed from 14 to 11. The download itself succeeded, but the file written to the microSD did not match the expected MD5 checksum published by the catalog.
What this error actually means
- The CDN request succeeded, but the Multi-device could not update the on-disk metadata for the newly downloaded microfirmware, or the on-disk copy did not match the expected MD5 checksum.
- Depending on where the operation failed, the UF2 file, the JSON descriptor, or both may be missing or truncated.
- The most common root cause is a weak or unstable Wi-Fi signal at the Multi-device location: even short drops mid-download corrupt the UF2 enough to fail the MD5 check.
Always confirm Wi-Fi signal quality first
Before touching the microSD card or reflashing the firmware, check the RSSI (signal strength in dBm) of the SIDECART connection to your home Wi-Fi. The only authoritative source for this value is the Multi-device itself, because only its on-board Pico W radio knows the real signal it is receiving:
- On the Atari ST, run Booster and open the Wi-Fi / connection status screen. The RSSI value (in dBm) is displayed there.
- Do not rely on phone or laptop signal readings as a substitute: they measure the radio inside that device, not the one inside the Multi-device, so they can be misleading.
Rule of thumb (2.4 GHz, typical for the Pico W):
| RSSI | Quality | What to expect |
|---|---|---|
| -30 to -55 dBm | Excellent | Wi-Fi is not the problem. |
| -56 to -67 dBm | Good | Downloads should still succeed reliably. |
| -68 to -75 dBm | Marginal | Intermittent MD5 mismatch (error 11 / error 14) failures expected. |
| -76 dBm or worse | Poor | This alone explains the failures; treat it as the root cause and improve Wi-Fi reception before anything else. |
If RSSI is marginal or worse, move the Atari ST closer to the access point, remove obstacles between them, or add a 2.4 GHz repeater/access point near the workstation. 5 GHz networks are not supported by the Pico W radio.
Inspect the microSD card
- Power off the ST and remove the Multi-device microSD card.
- Mount it on a PC/Mac/Linux host.
- Open the
/apps/folder. For every downloaded app you should see two files sharing the same UUIDv4 (example:123e4567-e89b-12d3-a456-426614174000.json+.uf2)..json(metadata) should be < 1 KB..uf2(microfirmware) should be approximately 1 MB.
Interpret the findings
| Observation | Likely cause | Next action |
|---|---|---|
Missing either the .json or .uf2 for the UUID | Network interrupted mid-write (even though the download appeared to finish) | Improve Wi-Fi reception (see above) and retry the download. |
Both files exist but the .uf2 is much smaller than 1 MB | Partial write (power loss / SD fault) | Delete the UUID pair, retry; if it persists, reformat the microSD card with the SD Card Formatter and reflash the firmware. |
| Both files exist with correct sizes, yet Booster still reports the same error | The flash storage on the Pico W could not accept the new firmware | Reflash the base firmware (see Restoring factory settings and the Firmware Installation section). |
Quick recovery steps
- Delete the incomplete UUID pair (both
.jsonand.uf2) from the/apps/folder on the microSD card. - Reboot the Atari ST, open Booster, and download the microfirmware again.
- If the same UUID fails twice, work through the root causes in this order:
- Wi-Fi signal quality (RSSI check above).
- Reformat the microSD card with the SD Card Formatter and try a fresh download.
- Reflash the base firmware as described in Restoring factory settings.
- After a successful retry, the new app shows in Booster without error 11 / 14, and
/apps/contains matching UUID pairs with the expected sizes.
Restoring factory settings
If you need to restore the factory settings of the Multi-device, you can do it by following these steps:
Pressing the SELECT button for more than 10 seconds
It does not matter if the Multi-device runs the Booster app or any of the available Microfirmware apps, pressing the SELECT button for more than 10 seconds will restore the factory settings of the Multi-device.
After powering off and on again, the classic factory settings screen will be displayed, allowing you to reconfigure the Multi-device from scratch as described in the Initial Factory Configuration section.
If the SELECT button does not work, please try powering on the Atari ST while holding the SELECT button pressed for more than 10 seconds.
If for any reason the SELECT button does not work, you can reflash the firmware of the Multi-device as described below.
Reflashing the firmware
If for any reason the above method does not work, you can reflash the firmware of the Multi-device by following the instructions in the Firmware Installation section.
Restore from the Bosster app
In the configuration section of the Booster app, there is an option to restore the factory settings of the Multi-device. After restoring the factory settings, the Multi-device will reboot and the classic factory settings screen will be displayed, allowing you to reconfigure the Multi-device from scratch as described in the Initial Factory Configuration section.
Floppy emulation
Some floppy disk images are not working. Games/applications are crashing
There are mostly two reasons why some floppy disk images are not working:
The floppy emulator “traps” the floppy disk access and redirects it to the microSD card. This is done by a combination of hardware and software. The hardware part is done by the Multi-device board and the software part is done by the firmware. The firmware is responsible for reading the floppy disk images from the microSD card and sending them to the Atari ST. Some applications -mostly games- are using a direct access to the floppy disk controller and bypass the operating system. In this case, the firmware is not able to redirect the floppy disk access to the microSD card. This is why some games/applications are not working. The only solution is to use another floppy disk image. As a workaround, I recommend to try a different version of the game/application from another collection or source.
The TOS version of your computer is not compatible with the application/game. In this case, you need to use a different TOS version, or find a version of the application/game compatible with your TOS version.
Hard disk emulation
Hard Disk Drive Not Visible in GEM
The hard disk drive is assigned to drive letter C (or another letter you’ve chosen), and it must be in uppercase. If the drive isn’t appearing, try the following steps: First, click on any ‘Floppy Disk’ icon. Next, navigate to the ‘Options’ menu located at the top of the screen and select ‘Install Disk Drive…’. Here, choose the letter C (or your specific drive letter), ensuring it’s in uppercase. For easier identification, change the Icon label to Hard Disk. After these adjustments, click on Install. You should now see the Drive C: (or your specified drive) displayed.
The hard disk drive letter of the GEMdrive collides with the drive letter of other devices
If the hard disk drive letter of the GEMdrive collides with the drive letter of other devices, you can change the drive letter of the GEMdrive in the configurator. To do this, instructions. Sometimes the drive letter of other devices cannot be changed, so you must change the drive letter of the GEMdrive.