> Complete documentation index: [llms.txt](/llms.txt). Markdown versions of all pages are available by appending `.md` to page URLs.

# Binho Supernova: Troubleshooting

> Fixes for a Binho Supernova that is not detected, stops responding or sits in its bootloader, and the Supernova's known limitations.

Find the symptom, then open the page. The steps are the same for the Supernova and the Pulsar, so each is written once and linked here.

| Symptom | Page |
| ------- | ---- |
| The adapter stops answering, times out, or resets itself | [Adapter Stops Responding](/support/troubleshooting/adapter-stops-responding/) |
| The adapter shows up as a USB drive or as "bootloader", or a firmware file is rejected | [Firmware and Bootloader](/support/troubleshooting/firmware-and-bootloader/) |
| The adapter is not found on Windows or macOS, or a Zadig driver broke it | [Windows and macOS](/support/troubleshooting/windows-and-macos/) |
| The adapter is not found on Linux, or its serial number is empty | [Solving USB Connection Issues on Linux](/support/troubleshooting/solving-usb-connection-issues-on-linux/) |
| [mc3.binho.io](https://mc3.binho.io) does not see or keep the adapter | [Mission Control 3 in the Browser](/support/troubleshooting/web-app/) |

## Specific to the Supernova

* In bootloader mode the adapter mounts a USB drive named **SUPERNOVA**. See [Firmware and Bootloader](/support/troubleshooting/firmware-and-bootloader/).
* Firmware for the Supernova is named `supernova-app-<version>.afx`. Never load Pulsar firmware on a Supernova. See [Firmware](/hardware/supernova/firmware/).
* Mission Control 2.16.1 and earlier do not work with Supernova firmware 4.x. Use [Mission Control 3](/software/mission-control/).
* On Linux the Supernova needs a `udev` rule, installed once. See [Solving USB Connection Issues on Linux](/support/troubleshooting/solving-usb-connection-issues-on-linux/).

Still stuck? Collect the details listed in [Collect Information for Support](/support/troubleshooting/adapter-stops-responding/#collect-information-for-support) and email [support@binho.io](mailto:support@binho.io).

## Known Limitations (firmware 4.6.x)

* **SPI reads above the wiring's clock ceiling** come back shifted by one bit with a success status. See [SPI](/hardware/supernova/protocols/#spi).
* **I3C SDR frame limit is 32,767 bytes**, register address included. A 32,768-byte frame reports success, drops the last byte and leaves the controller busy until it is re-initialized. PyCosmicSDK and CosmicSDK refuse it.
* **I3C IBI payload is at most 8 bytes**, and the target must end the IBI with the T-bit low. A longer IBI, or one that ends with the T-bit high, holds SDA low and blocks the bus.
* **An IBI that arrives on the same clock as a command header** is dropped and that command times out. Seen once in 3000 cycles with a target that requests an IBI whenever the bus is idle.
* **Legacy I2C on the I3C port** cannot run SDR, HDR or CCC commands while clock stretching is on.
* **I2C default timing** on 4.6.1 and earlier rounds some frequencies up (550 → 600 kHz), and a request above 3 MHz or below 11 Hz answers success while the bus runs at about 11 Hz. Set a duty cycle, or use 4.6.2 or later, which refuses out-of-range requests with `INVALID_PARAMETER`.
* **I2C target init after heavy large-transfer traffic** can time out until the adapter is reset. Reset the adapter before switching to I2C target mode.
* **SPI transfer of length 0** returns `0x000C` (unhandled error) on 4.6.1 and earlier.
* **SPI target mode** can skip the first byte sent in the first transaction after a role change. Later transactions are correct.
* **I3C target role** has no IBI or Hot-Join yet. The SETAASA CCC is not supported in target mode.

To update the firmware, see [Updating Firmware](/guides/firmware-updates/).