Helios64 SoC supports 3 boot modes that can be chosen by jumper configuration.
The default boot device order is:
1. SPI Flash
2. eMMC Flash
3. micro-SD Card
The SoC will access sequentially the above devices until it finds a bootloader code. To change the boot order if a bootloader code is present on more then one device, we can use the combination of P10 and P11 jumpers to force SoC to skip devices.
- P11 jumper can be used to disable SPI Flash, when this jumper is shorted SoC will skip looking for bootloader on SPI Flash and will continue with the EMMC Flash.
- P10 jumper can be used to disable eMMC Flash, when this jumper is shorted SoC will skip looking for bootloader on eMMC Flash and will continue with the micro-SD card.
The following logic table gives a simplified view of boot order configuration by jumper, assuming bootloader code is present on each device:
| P11 State | P10 State | Boot Order | Notes |
|-----------|-----------|------------|-------|
| 0 | 0 | SPI Flash | - |
| 1 | 0 | eMMC Flash | - |
| 1 | 1 | micro-SD Card | - |
## USB Console/Recovery Mode (P13)
This jumper controls a 2:1 MUX switching the USB2.0 lanes of the Type-C port (J15) between the SoC Type-C interface and the USB-to-Serial bridge. For more details refer to the [USB Type-C section](/helios64/usb/#usb-on-helios64).
You can plug both DC-IN inputs in order to have a failover setup that automatically switches to the other input if the first one fails. Jumpers P15 can be used to force ATX as master DC-IN input.
