Excuse me, in ARMV5 CPU, the kernel 4.14, use ubifs as root, but after the root mount success, wait a minute in the shutdown and restart will appear
[9.480000] UBI error: ubi_io_read: error 126976-74 (ECC error) while reading bytes from PEB 73:4096, 94208 bytes read

Analyses the reason of down should be the kernel to write the log, but the root fs cannot be set to a read/write, if nand driver problem, the root fs first mount itself and there are no mistakes, uboot set and the kernel is consistent with the basic part of the driver,
Master please help to give directions, just said some debugging direction, very grateful