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→Available options
Interested reader may find an exhaustive discussion of iMX6UL boot options in the ''Applications Processor Reference Manual''<ref name="IMX6ULRM">NXP, IMX6ULRM, ''i.MX 6UltraLite Applications Processor Reference Manual''</ref>.
==Available options==
By default, eFUSE bits are not supported as bootstrap option [1]. Thus , two actual modes can be selected by S12.1 and S12.2 switches, as listed in the following table.{|class="wikitable" style="text-align: center;"
|-
!BOOT_MODE[1:0]
!Notes
|-
| 00||Boot from eFUSEs||off||off||'''Supported on request only''Default:''''' boot from external SD card
|-
| 01||Serial downloader||off||on||
|-
| 10||Internal boot||on||off||DefaultBoot from NOR SPI (default internal storage)
|-
| 11||reserved|| on || on || '''Reserved'''
|}
[1] Nevertheless, SBC Lynx can support this option. This is a clear example of a feature that can be implemented on request. For more information please contact [mailto:sales@dave.eu Sales department].
The following table summarizes these configurations. Pull-up/down resistors are 10kOhm.
{|class="wikitable" style="text-align: center;"
|-
!Ordering code(s) →<br>-----<br><code>BOOT_CFG</code> bits<br>↓!XUBx0xxx<br>XUBx2xxx!XUBx1xxxPull
|-
| LCD_DATA23 (BOOT_CFG4_7) || pull-down || TBD
|-
| LCD_DATA22 (BOOT_CFG4_6) || pull-down || TBD
|-
| LCD_DATA21 (BOOT_CFG4_5) || pull-down || TBD
|-
| LCD_DATA20 (BOOT_CFG4_4) || pull-down || TBD
|-
| LCD_DATA19 (BOOT_CFG4_3) || pull-up || TBD
|-
| LCD_DATA18 (BOOT_CFG4_2) || pull-down || TBD
|-
| LCD_DATA17 (BOOT_CFG4_1) || pull-down || TBD
|-
| LCD_DATA16 (BOOT_CFG4_0) || pull-down || TBD
|-
| LCD_DATA15 (BOOT_CFG2_7) || pull-up || TBD
|-
| LCD_DATA14 (BOOT_CFG2_6) || pull-up || TBD
|-
| LCD_DATA13 (BOOT_CFG2_5) || pull-up || TBD
|-
| LCD_DATA12 (BOOT_CFG2_4) || pull-up || TBD
|-
| LCD_DATA11 (BOOT_CFG2_3) || pull-up || TBD
|-
| LCD_DATA10 (BOOT_CFG2_2) || pull-down || TBD
|-
| LCD_DATA09 (BOOT_CFG2_1) || pull-up || TBD
|-
| LCD_DATA08 (BOOT_CFG2_0) || pull-up || TBD
|-
| LCD_DATA07 (BOOT_CFG1_7) || pull-down || TBD
|-
| LCD_DATA06 (BOOT_CFG1_6) || pull-down || TBD
|-
| LCD_DATA05 (BOOT_CFG1_5) || pull-up || TBD
|-
| LCD_DATA04 (BOOT_CFG1_4) || pull-up || TBD
|-
| LCD_DATA03 (BOOT_CFG1_3) || pull-up || TBD
|-
| LCD_DATA02 (BOOT_CFG1_2) || pull-up || TBD
|-
| LCD_DATA01 (BOOT_CFG1_1) || pull-up || TBD
|-
| LCD_DATA00 (BOOT_CFG1_0) || pull-up || TBD
|}
The following chart depicts the general boot flow of SBC Lynx models equipped with NOR flash. It is worth noticing that, if the flow falls in the ''serial downloader'' branch, the BootROM performs an attempt to boot from microSD card too, as the ''Manufacture mode'' is enabled. This mode can be a convenient solution for different needs (for example, to recover a board where U-Boot was erased accidentally from NOR flash). For more information, please refer to [[How_to_create_a_bootable_microSD_card_(XUELK)|this page]] and [[Standalone_boot_(XUELK)#U-Boot|this page]].
[[File:SBCLynx-boot-XUBx0000.png|thumb|center|600px|Boot flow of ordering codes XUBx0000]]
===Serial downloader===
Generally speaking, serial downloader allows to download downloading a program image to the target over USB or UART connections. The following flow chart flowchart details the sequence of operations that are performed by BootROM in Serial Download mode (source ''Applications Processor Reference Manual''<ref name="IMX6ULRM"></ref>.
In case <span id="manuf_mode">''Manufacture mode''</span> is enabled, before probing UART and /USB interfacesinterface, BootROM tries to boot from SDHC1 interface if any device is connected to it. The following sections provides additional notes related to the use of Serial Downloader on SBC Lynx in order to warn the user about possible conflicts that may occur depending on what is connected to USBOTG1 port, UART1 and UART2 interfaces.=====Ordering codes XUBx0000=====UART1: this UART is routed to connector J42 that is typically used for console.
==References==
{{reflist}}