Hi,
According to Blaze's video tutorials ("http://omappedia.org/wiki/Blaze_Video_Tutorials" second video) the correct configuration for S2 when booting from SD card is : OFF ON OFF OFF ON OFF OFF OFF". This is different from what is mentioned in ice cream sandwich release notes (http://www.omappedia.com/wiki/L27.IS.2.P2_OMAP4_Icecream_Sandwich_Release_Notes) which is OFF ON OFF ON ON ON OFF ON. Am I missing something? In fact, I can boot from SD card only with the configuration mentioned in the video tutorials.
Alireza
Hi Alireza,I have tried both the S2 switch configurations namely "OFF ON OFF OFF ON OFF OFF OFF" from video tutorial & "OFF ON OFF ON ON ON OFF ON" from ICS Release Notes on the Blaze Board with Daughter Card SEVM4430E and ES 2.3 Emu OMAP4430 SOM.It boots without any issue from SD Card for both configurations of S2 DIP switch.Could you please let us know which board version and SOM module you are using to further understand the differences?Thanks & Best Regards,Venkat
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Alireza,
To better understand the meaning of the S2 switch configuration, see Tables 27-7 and 27-8 in the OMAP TRM:
http://www.ti.com/general/docs/wtbu/wtbudocumentcenter.tsp?templateId=6123&navigationId=12037#65
The S2 switch defines the SYSBOOT pins, which setup the booting device list. This is the ordered list of devices (such as SD card, eMMC, and USB) that the ROM code will search for a valid x-loader.
The switch settings mentioned in the release notes:
For Blaze & Blaze_Tablet board: Switch S2-(1:8): OFF ON OFF ON ON ON OFF ON
means sys_boot[5:0] = 000101
which gives a booting device list of USB followed by MMC1 (SD card).
The switch settings from the video tutorial: "OFF ON OFF OFF ON OFF OFF OFF"
means sys_boot[5:0] = 101101
which gives a booting device list of MMC1 followed by UART.
There are several different combinations of switch settings you could use to boot from MMC1,
and both of these should work.
Regards,
Gina
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comment;
from the L27.IS2P1 link it says "First time flashing on eMMC" and using the links that Gina shared,
When flashing for eMMC fastboot needs to boot from SD Card first to program eMMC with xloader and uboot then it restarts and process recalculates images sizes and finishes the eMMC flashing. After in the link they mention to use other switch configuration to boot from eMMC.
if incorrect switch configuration is not used when process reboots it will not run, this configuration seems to be for use in this process of flashing eMMC not for use in SD Card systems. it could require some check to find if it is compatible with SD Card booting.