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

# Binho Pulsar: Troubleshooting

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

Find the symptom, then open the page. The steps are the same for the Pulsar and the Supernova, 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 | [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 Pulsar

* In bootloader mode the adapter mounts a USB drive named **PULSAR**. See [Firmware and Bootloader](/support/troubleshooting/firmware-and-bootloader/).
* Firmware for the Pulsar is named `pulsar-app-<version>.afx`. Never load Supernova firmware on a Pulsar. See [Firmware](/hardware/pulsar/firmware/).
* Mission Control 2.16.1 and earlier do not work with Pulsar firmware 4.x. Use [Mission Control 3](/software/mission-control/).
* The Pulsar appears as both a USB HID device and a USB serial port. If the serial port is missing, or behaves as RS-485 or CAN-FD when UART is expected, check the mode: [Virtual COM Port Modes](/hardware/pulsar/protocols/#virtual-com-port-modes-rs-485-and-can-fd).
* On Linux the Pulsar needs a `udev` rule, installed once. See [Solving USB Connection Issues on Linux](/support/troubleshooting/solving-usb-connection-issues-on-linux/).

## Known limitations (firmware 4.6.x)

* **VTARG on 4.6.x and earlier:** a voltage Set connects the Pulsar's supply onto a self-powered target. Use `use_external_voltage()` with a self-powered target.
* **SPI reads above the wiring's clock ceiling** come back shifted one bit, reported as success. Read at a conservative clock and bound flash `WIP` polls.
* **A 0-byte SPI controller transfer** returns `0x000C` on 4.6.1 and earlier; 4.6.2 returns `INVALID_PARAMETER`. Do not send 0-byte transfers.
* **I2C default timing on 4.6.1 and earlier:** without a duty cycle, some frequencies run above the request (550 kHz → 600 kHz), and a rate above 3 MHz or below 11 Hz answers success while the bus runs at about 11 Hz. Set a duty cycle, or use 100 kHz, 400 kHz or 1 MHz.
* **I2C target mode after heavy 16 KB bulk traffic** can time out when it is armed. Reset the adapter before arming target mode.
* **SPI target mode** can skip the first byte sent back in the first transaction after a role change. Ignore the first transaction, or re-arm.
* **CAN-FD mode:** 16 KB bulk transfers are unavailable while the serial port is in CAN-FD mode. Switch back to UART pass-through for bulk work.

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).