Why is U-Boot not able to configure the Agilex™ 5 and Agilex™ 3 SDMMC controller in 8-bit bus width when booting from eMMC in releases 25.1.1 and before, regardless of bus-width = <8>; parameter is defined in the device tree? - Why is U-Boot not able to configure the Agilex™ 5 and Agilex™ 3 SDMMC controller in 8-bit bus width when booting from eMMC in releases 25.1.1 and before, regardless of bus-width = <8>; parameter is defined in the device tree? Description Due to a silicon problem in Agilex™ 5 and Agilex™ 3 devices, the SRS16 capability register of the SDMMC controller incorrectly reports in the EDS8 bit (bit 18) that the controller does not support the eMMC 8-bit bus width mode. As a result, the U-Boot eMMC driver identifies 4-bit mode as the maximum supported width and configures the controller accordingly. This occurs even if the bus-width parameter is explicitly set to 8 in the device tree. Resolution To work around this problem, use the sdhci-caps and sdhci-caps-mask parameters in the U-Boot device tree to override the incorrectly reported values in the capability registers ( SRS16 and SRS17 ). For this case, override bit 18 in SRS16 to indicate that an 8-bit bus width is supported. Example configuration: &mmc { status = "okay"; bus-width = <8>; sdhci-caps = <0x00000000 0x00040000>; sdhci-caps-mask = <0x00000000 0x00040000>; sd-uhs-sdr50; cap-mmc-highspeed; bootph-all; }; Verification in U-Boot : After applying the workaround, you can verify that the controller is using an 8-bit bus width by running the mmc info command: SOCFPGA_AGILEX5 # mmc info Device: mmc0@10808000 Manufacturer ID: 13 OEM: 4e Name: G1M15L Bus Speed: 52000000 Rd Block Len: 512 MMC version 5.1 High Capacity: Yes Capacity: 29.6 GiB Bus Width: 8-bit Erase Group Size: 512 KiB HC WP Group Size: 8 MiB User Capacity: 29.6 GiB WRREL Boot Capacity: 31.5 MiB ENH RPMB Capacity: 4 MiB ENH Boot area 0 is not write protected Boot area 1 is not write protected This workaround will be permanently implemented in the Agilex™ 5/Agilex™ 3 U-Boot device tree in a future release of the FPGA HPS Embedded Software. Custom Fields values: Troubleshooting 14025822342 ['FPGA Dev Tools Quartus® Prime Software Pro'] 25.1.1 ['Agilex™ 5 FPGAs and SoCs', 'Agilex™ 3 FPGAs and SoCs']