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If MX1 = 0, the JTAG interface of CA55 of SP7350 will be enabled.
If MX2 = 0, SP7350 will enter test mode. Always set to 1 for normal operation.
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i-boot log and explanation
Line 1: Banner The banner (version) of i-boot
Line 4: Boot-mode is 0x1F (MX[6..2]), indicating eMMC boot.
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