topic how to boot iMX8M Nano from uSDHC1 emmc in i.MX Processors

how to boot iMX8M Nano from uSDHC1 emmc

x10 — Fri, 04 Dec 2020 08:02:34 GMT

My design requires to boot iMX8MN from uSDHC emmc 8-bit. As my understanding, the following settings are essential:

(1) BOOT_MODE_PIN = 0010b ---> uSDHC3 emmc 8-bit as boot device

(2) OCOTP_BOOT_CFG0 = 0x0000_0a00 ---> override uSDHC with uSDHC1 emmc

My question: do the fuse bits in BOOT_CFG0 register become valid without BT_FUSE_SEL blown?

Thanks in advance!

Cheng Shi

Re: how to boot iMX8M Nano from uSDHC1 emmc

Rita_Wang — Mon, 08 Feb 2021 10:47:52 GMT

Yes, 0x470[15:0] BOOT_CFG 16 BOOT configuration register, Usage varies, depending on selected boot device. And BT_FUSE_SEL is Determines, whether using fuses for boot configuration, or GPIO /Serial loader.

Re: how to boot iMX8M Nano from uSDHC1 emmc

x10 — Tue, 09 Feb 2021 03:15:51 GMT

uSDHC1 boot implemented with following settings:

(1) CFG pins configured as uSDHC3(emmc) boot mode

(2) eFuse.470 => 0x0000_2a000 to override to uSDHC1 boot

The important point is keeping BT_FUSE_SEL un-burn, so that manufacture SD2 boot can be triggered by changing CFG pins settings, which is required in boot image update.