We would like to test various options from booting from EMMC on IMX8QX MEK:
1. EMMC fastboot mode
2. EMMC high speed
3. EMMC bus width selection.
From the Reference Manual (IMX8DQXPRM) section 220.127.116.11 (Boot Devices -> Expansion Device eFUSE configuration), I understand that the eFUSE needs to be programmed to select the above boot options. However, blowing eFUSE is a one time operation, which cannot be reverted.
I tried to use the 'fuse override' command from u-boot, but it fails with the message 'Override fuse to i.MX8 in u-boot is forbidden'. Also, as I understand, the override setting will be lost on reset. However, the boot mode testing can only be done by resetting the board, so the override will not be useful.
Is there a way to test the above modes without permanently programming eFUSE bits?