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Testing EMMC fastboot mode on IMX8QX MEK

Question asked by Komal Padia on Jul 5, 2019
Latest reply on Jul 5, 2019 by igorpadykov

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 5.8.2.1 (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?

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