Hi,
I posted this previously and it was confirmed from nxp that for eFuses to work, we must have the default SD2 pins assigned to the SD slot to boot from SD 2 with eFuses. : https://community.nxp.com/t5/i-MX-Processors/I-MX6ULZ-eFuse-boot-from-SD-with-custom-pinmux-for-SD-s...
However, now we are attempting to make the changes on our board and are having a difficult time understanding which actually the default SD2 slot pins are.
So as an example lets take SD2_CLK signal. Based on the RM the USDHC2 CLK can be routed to SD2_CLK, GPIO3_IO24, and NAND_RE_B pins/pads. But ALT1 mode is for only SD2_CLK and NAND_RE_B. We used SD2_CLK as this seems like the default SD2 clock pin. However, on the 6ull EVK they are actually using the NAND_RE_B for SD2_CLK and similarly the rest of the SD2 signals are also different and related to NAND instead of SD2 (e.g NAND_WE_B instead of SD2_CMD).
We blew the eFuses and the fuse values were read correct afterwards but could not boot to u-boot or OS. We can boot the OS fine via Serial downloader mode so all other operations are verified to work. Fuse values set and read below.
fuse prog 0 6 0x10
fuse prog 0 5 0x2840
So, ultimately our question is, which are the default pins for the SD2 signals that the ROM code looks in order to boot? the SD2_XXX or NAND_XXXX? If it is NAND_XXX, why is it that one? Or does it look at both?
The reference manual table :
And our schematics for SD2 slot is as follows:
Reference design Schematic snippet from the EVK schematic file.
