topic Re: Troubleshooting 8ULP EVK Boot Fuses in i.MX Processors

Troubleshooting 8ULP EVK Boot Fuses

KipW — Mon, 27 Oct 2025 20:19:46 GMT

I am testing recovery methods using the MCIMX8ULP-BB EVK. I successfully burned BT_FUSE_SEL and BT0_CFG1 (Boot from A35/eMMC and M33/QSPI) using u-boot's fuse command. When I set my boot pins to "00" I get the serial bootloader. However, since I have working images in A35's eMMC and M33's NOR, I should be seeing the the kernel boot and the output from M33's image.

Ideas on how to troubleshoot this? Does booting from the fuses *require* that I use signed/secure images?

Re: Troubleshooting 8ULP EVK Boot Fuses

Chavira — Tue, 28 Oct 2025 17:14:38 GMT

HI @KipW,

For that usage you should flash the images following the next instructions:

To burn dual-boot image and rootfs to eMMC and FlexSPI0 NOR flash, perform the following steps:

1. Prepare imx-boot-imx8ulpevk-sd.bin-flash_singleboot_m33, imx-boot-imx8ulpevk-
sd.bin-flash_dualboot, imx-boot-imx8ulpevk-sd.bin-flash_dualboot_m33, and
<rootfs.wic>.

2. Update the UUU script file uuu_8ulp_dual.auto with the file path and name of the images above.

3. Run uuu mfgtools/scripts/samples/uuu_8ulp_dual.auto.
For detailed usage of UUU, see github.com/NXPmicro/mfgtools/wiki.

Re: Troubleshooting 8ULP EVK Boot Fuses

KipW — Wed, 29 Oct 2025 15:08:59 GMT

I pulled down LF_v6.12.34-2.1.0_images_IMX8ULPEVK, updated the samples/uuu_8ulp_dual.auto to point to the local bin files, burned the images and same result.

When I POR, with Boot Switch set to xxxx_xx00, I see nothing and the SDPS device appears. I do not have any SRK or certs or any of the CST set up.

Re: Troubleshooting 8ULP EVK Boot Fuses

KipW — Thu, 30 Oct 2025 16:27:49 GMT

Turns out that the 'fuse' command in u-boot requires a little-endian value for burning. The u-boot command does not perform the endian swap for you