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If you upload to a SAMD board like the MKR boards or the Nano 33 IoT with Nano 33 BLE selected in Tools menu of Arduino IDE, the upload is executed and deletes the bootloader of the SAMD MCU.

The problem is that bossac uploader doesn't check the chip, because it was developed only for the SAMD chips, but Arduino created a bootloader for the Nano 33 BLE nRF52 MCU to use the SAMD bossac uploader.

The SAMD boards use the native USB support of the MCU, so without a bootloader or good sketch running the USB doesn't work.

You have to restore the bootloader on Nano 33 IoT. It is done over the SWD pads on the bottom side of the board. You can use a SWD programmer or other Arduino board with the Adafruit DAP library.

According to this article Atmel ICE can be used for SWD programming. Do the wiring and then select in Tools menu the right board, the Atmel EDBG programmer and use Burn bootloader command.

I had this problem with MKR Zero and I used a LPC-Link2 programmer to burn the bootloader. Once before I lost the bootloader for other reason and back then I didn't have the programmer so I used the Adafruit DAP library with an Arduino M0.

If you upload to a SAMD board like the MKR boards or the Nano 33 IoT with Nano 33 BLE selected in Tools menu of Arduino IDE, the upload is executed and deletes the bootloader of the SAMD MCU.

The problem is that bossac uploader doesn't check the chip, because it was developed only for the SAMD chips, but Arduino created a bootloader for the Nano 33 BLE nRF52 MCU to use the SAMD bossac uploader.

The SAMD boards use the native USB support of the MCU, so without a bootloader or good sketch running the USB doesn't work.

You have to restore the bootloader on Nano 33 IoT. It is done over the SWD pads on the bottom side of the board. You can use a SWD programmer or other Arduino board with the Adafruit DAP library.

You can use your Nano 33 BLE or some other board and a SD card with Adafruit DAP library as programmer.

I had this problem with MKR Zero and I used a LPC-Link2 programmer to burn the bootloader. Once before I lost the bootloader for other reason and back then I didn't have the programmer so I used the Adafruit DAP library with an Arduino M0.

If you upload to a SAMD board like the MKR boards or the Nano 33 IoT with Nano 33 BLE selected in Tools menu of Arduino IDE, the upload is executed and deletes the bootloader of the SAMD MCU.

The problem is that bossac uploader doesn't check the chip, because it was developed only for the SAMD chips, but Arduino created a bootloader for the Nano 33 BLE nRF52 MCU to use the SAMD bossac uploader.

You have to restore the bootloader on Nano 33 IoT. It is done over the SWD pads on the bottom side of the board. You can use a SWD programmer or other Arduino board with the Adafruit DAP library.

According to this article Atmel ICE can be used for SWD programming. Do the wiring and then select in Tools menu the right board, the Atmel EDBG programmer and use Burn bootloader command.

I had this problem with MKR Zero and I used a LPC-Link2 programmer to burn the bootloader. Once before I lost the bootloader for other reason and back then I didn't have the programmer so I used the Adafruit DAP library with an Arduino M0.

If you upload to a SAMD board like the MKR boards or the Nano 33 IoT with Nano 33 BLE selected in Tools menu of Arduino IDE, the upload is executed and deletes the bootloader of the SAMD MCU.

The problem is that bossac uploader doesn't check the chip, because it was developed only for the SAMD chips, but Arduino created a bootloader for the Nano 33 BLE nRF52 MCU to use the SAMD bossac uploader.

The SAMD boards use the native USB support of the MCU, so without a bootloader or good sketch running the USB doesn't work.

You have to restore the bootloader on Nano 33 IoT. It is done over the SWD pads on the bottom side of the board. You can use a SWD programmer or other Arduino board with the Adafruit DAP library.

According to this article Atmel ICE can be used for SWD programming. Do the wiring and then select in Tools menu the right board, the Atmel EDBG programmer and use Burn bootloader command.

I had this problem with MKR Zero and I used a LPC-Link2 programmer to burn the bootloader. Once before I lost the bootloader for other reason and back then I didn't have the programmer so I used the Adafruit DAP library with an Arduino M0.

If you upload to a SAMD board like the MKR boards or the Nano 33 IoT with Nano 33 BLE selected in Tools menu of Arduino IDE, the upload is executed and deletes the bootloader of the SAMD MCU.

The problem is that bossac uploader doesn't check the chip, because it was developed only for the SAMD chips, but Arduino created a bootloader for the Nano 33 BLE nRF52 MCU to use the SAMD bossac uploader.

You have to restore the bootloader on Nano 33 IoT. It is done over the SWD pads on the bottom side of the board. You can use a SWD programmer or other Arduino board with the Adafruit DAP library.

According to this article Atmel ICE can be used for SWD programming. Do the wiring and then select in Tools menu the right board, the Atmel EDBG programmer and use Burn bootloader command.

I had this problem with MKR Zero and I used a LPC-Link2 programmer to burn the bootloader. Once before I lost the bootloader for unknown reason and back then I didn't have the programmer so I used the Adafruit DAP library with an Arduino M0.

If you upload to a SAMD board like the MKR boards or the Nano 33 IoT with Nano 33 BLE selected in Tools menu of Arduino IDE, the upload is executed and deletes the bootloader of the SAMD MCU.

The problem is that bossac uploader doesn't check the chip, because it was developed only for the SAMD chips, but Arduino created a bootloader for the Nano 33 BLE nRF52 MCU to use the SAMD bossac uploader.

You have to restore the bootloader on Nano 33 IoT. It is done over the SWD pads on the bottom side of the board. You can use a SWD programmer or other Arduino board with the Adafruit DAP library.

According to this article Atmel ICE can be used for SWD programming. Do the wiring and then select in Tools menu the right board, the Atmel EDBG programmer and use Burn bootloader command.

I had this problem with MKR Zero and I used a LPC-Link2 programmer to burn the bootloader. Once before I lost the bootloader for other reason and back then I didn't have the programmer so I used the Adafruit DAP library with an Arduino M0.