# External boot devices

Source: [https://docs.qualcomm.com/doc/80-PV086-5P/topic/external-boot-devices.html](https://docs.qualcomm.com/doc/80-PV086-5P/topic/external-boot-devices.html)

The following table lists the GPIOs for external boot.

| FAST\_BOOT GPIO [3:0] | GPIO no. | GPIO no. | GPIO no. | GPIO no. | Boot device |
| --- | --- | --- | --- | --- | --- |
| FAST\_BOOT GPIO [3:0] | 90 | 76 | 47 | 27 | Boot device |
| 0000 | 0 | 0 | 0 | 0 | Default: UFS0 → SDC2 → USB0 → eDL (USB0) |
| 0001 | 0 | 0 | 0 | 1 | SDC2 → UFS0 → eDL (USB0) |
| 0010 | 0 | 0 | 1 | 0 | SDC2 → eDL (USB0) |
| 0011 | 0 | 0 | 1 | 1 | USB0 → eDL (SDC2 → USB0) |
| 0100 | 0 | 1 | 0 | 0 | QSPI → eDL (SDC2 → USB0) |
| 0101 | 0 | 1 | 0 | 1 | SPI → eDL (SDC2 → USB0) |
| 0110 | 0 | 1 | 1 | 0 | UFS0 → USB0 → eDL (USB0) |
| 0111 | 0 | 1 | 1 | 1 | Same as Fastboot[3:0] = 0000<br><br><br>              <br>UFS0 → SDC2 → USB0 → eDL (USB0) |
| Others | Others | Others | Others | Others | Reserved |
|  |  |  |  |  |  |

Note: 
      
- eDL – Emergency Download. Boot from SD is not supported if PM8250 boot option pin GPIO\_05 is grounded. For details, see the *PM8150/PM8250 Device Specification* (80-PD995-1).
- The FASTBOOT[4] fuse in OEM\_CONFIG region of QFPROM does not have a corresponding GPIO. See the *QRB5165 QFPROM Programming Reference Guide* (80-PV086-97) for fuses related to FASTBOOT settings and their impact on the boot device selection and boot flow.

**Parent Topic:** [Boot configuration and memory](https://docs.qualcomm.com/doc/80-PV086-5P/topic/boot-configuration-and-memory.html)

Last Published: Jul 07, 2023

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