Why there are ecc errors? nand ecc error?

Starting kernel ...

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.14.180 (builder@buildhost) (gcc version 7.5.0 (OpenWrt GCC 7.5.0 r11063-85e04e9f46)) #0 SMP Sat May 16 18:32:20 2020
[    0.000000] CPU: ARMv6-compatible processor [410fb025] revision 5 (ARMv7), cr=00c5787d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[    0.000000] OF: fdt: Machine model: Cloud Engines PogoPlug Pro
[    0.000000] Memory policy: Data cache writealloc
[    0.000000] cma: Reserved 64 MiB at 0x64000000
[    0.000000] random: get_random_bytes called from 0xc07008b4 with crng_init=0
[    0.000000] percpu: Embedded 15 pages/cpu s29100 r8192 d24148 u61440
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 32512
[    0.000000] Kernel command line: earlyprintk console=ttyS0,115200
[    0.000000] Bootloader command line (ignored): root=ubi0:rootfs ubi.mtd=2,512 rootfstype=ubifs console=ttyS0,115200 elevator=cfq mac_adr=0x00,0x30,0xe0,0x00,0x00,0x01 mem=128M poweroutage=yes
[    0.000000] PID hash table entries: 512 (order: -1, 2048 bytes)
[    0.000000] Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)
[    0.000000] Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)
[    0.000000] Memory: 56564K/131072K available (5120K kernel code, 128K rwdata, 616K rodata, 1024K init, 207K bss, 8972K reserved, 65536K cma-reserved)
[    0.000000] Virtual kernel memory layout:
[    0.000000]     vector  : 0xffff0000 - 0xffff1000   (   4 kB)
[    0.000000]     fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
[    0.000000]     vmalloc : 0xc8800000 - 0xff800000   ( 880 MB)
[    0.000000]     lowmem  : 0xc0000000 - 0xc8000000   ( 128 MB)
[    0.000000]     modules : 0xbf000000 - 0xc0000000   (  16 MB)
[    0.000000]       .text : 0xc0008000 - 0xc0600000   (6112 kB)
[    0.000000]       .init : 0xc0700000 - 0xc0800000   (1024 kB)
[    0.000000]       .data : 0xc0800000 - 0xc08201e0   ( 129 kB)
[    0.000000]        .bss : 0xc08238a0 - 0xc0857648   ( 208 kB)
[    0.000000] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=2, Nodes=1
[    0.000000] Hierarchical RCU implementation.
[    0.000000]  RCU event tracing is enabled.
[    0.000000]  RCU restricting CPUs from NR_CPUS=16 to nr_cpu_ids=2.
[    0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=2
[    0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
[    0.000000] FPGA IRQ chip 0 "interrupt-controller" @ c8804000, 32 irqs, parent IRQ: 16
[    0.000023] sched_clock: 24 bits at 390kHz, resolution 2560ns, wraps every 21474835200ns
[    0.000056] clocksource: oxnas_rps_clocksource_timer: mask: 0xffffff max_cycles: 0xffffff, max_idle_ns: 19112603332 ns
[    0.000071] timer_oxnas_rps: Registered clocksource rate 390625Hz
[    0.000102] timer_oxnas_rps: Registered clock event rate 6250000Hz prescaler 0 period 62500
[    0.000281] GIC: PPI13 is secure or misconfigured
[    0.000340] GIC: PPI13 is secure or misconfigured
[    0.000453] Calibrating delay loop... 278.93 BogoMIPS (lpj=1394688)
[    0.070356] pid_max: default: 32768 minimum: 301
[    0.070551] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[    0.070581] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[    0.071441] CPU: Testing write buffer coherency: ok
[    0.072842] Setting up static identity map for 0x60100000 - 0x6010005c
[    0.073111] Hierarchical SRCU implementation.
[    0.074073] smp: Bringing up secondary CPUs ...
[    0.075064] GIC: PPI13 is secure or misconfigured
[    0.140631] smp: Brought up 1 node, 2 CPUs
[    0.140664] SMP: Total of 2 processors activated (557.87 BogoMIPS).
[    0.145832] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.145871] futex hash table entries: 512 (order: 2, 16384 bytes)
[    0.151897] pinctrl core: initialized pinctrl subsystem
[    0.152686] NET: Registered protocol family 16
[    0.157184] DMA: preallocated 256 KiB pool for atomic coherent allocations
[    0.159777] cpuidle: using governor menu
[    0.159882] No ATAGs?
[    0.173752] pps_core: LinuxPPS API ver. 1 registered
[    0.173777] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it>
[    0.173834] PTP clock support registered
[    0.174863] clocksource: Switched to clocksource oxnas_rps_clocksource_timer
[    0.176371] NET: Registered protocol family 2
[    0.177384] TCP established hash table entries: 1024 (order: 0, 4096 bytes)
[    0.177433] TCP bind hash table entries: 1024 (order: 1, 8192 bytes)
[    0.177472] TCP: Hash tables configured (established 1024 bind 1024)
[    0.177648] UDP hash table entries: 256 (order: 1, 8192 bytes)
[    0.177702] UDP-Lite hash table entries: 256 (order: 1, 8192 bytes)
[    0.177999] NET: Registered protocol family 1
[    0.179619] No memory allocated for crashlog
[    0.179934] workingset: timestamp_bits=30 max_order=15 bucket_order=0
[    0.187558] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[    0.191603] io scheduler noop registered
[    0.191631] io scheduler deadline registered
[    0.191897] io scheduler cfq registered (default)
[    0.194401] Serial: 8250/16550 driver, 16 ports, IRQ sharing enabled
[    0.199144] console [ttyS0] disabled
[    0.199288] 44200000.serial: ttyS0 at MMIO 0x44200000 (irq = 55, base_baud = 390625) is a 16550A
[    0.673840] console [ttyS0] enabled
[    0.693109] brd: module loaded
[    0.705305] loop: module loaded
[    0.775196] nand: Could not find valid ONFI parameter page; aborting
[    0.781537] nand: device found, Manufacturer ID: 0xad, Chip ID: 0xf1
[    0.787919] nand: Hynix NAND 128MiB 3,3V 8-bit
[    0.792348] nand: 128 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64
[    0.799930] Scanning device for bad blocks
[    0.889349] 5 fixed-partitions partitions found on MTD device 41000000.nand-controller
[    0.897267] Creating 5 MTD partitions on "41000000.nand-controller":
[    0.903600] 0x000000000000-0x000000040000 : "stage1"
[    0.909903] 0x000000040000-0x0000003c0000 : "u-boot"
[    0.916111] 0x0000003c0000-0x000000440000 : "u-boot-env"
[    0.922577] 0x000000440000-0x000000e00000 : "kernel"
[    0.928898] 0x000000e00000-0x000008000000 : "ubi"
[    0.936250] libphy: Fixed MDIO Bus: probed
[    0.941084] oxnas-dwmac 40400000.ethernet: PTP uses main clock
[    0.946992] oxnas-dwmac 40400000.ethernet: no reset control found
[    1.014960] stmmac - user ID: 0x12, Synopsys ID: 0x35
[    1.020006] oxnas-dwmac 40400000.ethernet: Ring mode enabled
[    1.025707] oxnas-dwmac 40400000.ethernet: DMA HW capability register supported
[    1.032990] oxnas-dwmac 40400000.ethernet: Enhanced/Alternate descriptors
[    1.039787] oxnas-dwmac 40400000.ethernet: Enabled extended descriptors
[    1.046407] oxnas-dwmac 40400000.ethernet: RX Checksum Offload Engine supported
[    1.053685] oxnas-dwmac 40400000.ethernet: COE Type 2
[    1.058752] oxnas-dwmac 40400000.ethernet: TX Checksum insertion supported
[    1.065633] oxnas-dwmac 40400000.ethernet: Wake-Up On Lan supported
[    1.071984] oxnas-dwmac 40400000.ethernet (unnamed net_device) (uninitialized): device MAC address da:50:34:0d:04:a3
[    1.082511] oxnas-dwmac 40400000.ethernet: Enable RX Mitigation via HW Watchdog Timer
[    1.100213] libphy: stmmac: probed
[    1.103621] RTL8211DN Gigabit Ethernet stmmac-0:00: attached PHY driver [RTL8211DN Gigabit Ethernet] (mii_bus:phy_addr=stmmac-0:00, irq=POLL)
[    1.116349] RTL8211DN Gigabit Ethernet stmmac-0:03: attached PHY driver [RTL8211DN Gigabit Ethernet] (mii_bus:phy_addr=stmmac-0:03, irq=POLL)
[    1.131453] ledtrig-cpu: registered to indicate activity on CPUs
[    1.137630] hidraw: raw HID events driver (C) Jiri Kosina
[    1.144483] NET: Registered protocol family 10
[    1.150830] Segment Routing with IPv6
[    1.154598] NET: Registered protocol family 17
[    1.159255] bridge: filtering via arp/ip/ip6tables is no longer available by default. Update your scripts to load br_netfilter if you need this.
[    1.424898] oxnas-pcie 47c00000.pcie-controller: PCIe version/deviceID 0x82510b5
[    2.434821] oxnas-pcie 47c00000.pcie-controller: link down
[    2.440634] oxnas-pcie 47c00000.pcie-controller: PCI host bridge to bus 0000:00
[    2.447997] pci_bus 0000:00: root bus resource [mem 0x48000000-0x49ffffff]
[    2.454888] pci_bus 0000:00: root bus resource [mem 0x4a000000-0x4bdfffff pref]
[    2.462172] pci_bus 0000:00: root bus resource [io  0x0000-0xfffff]
[    2.468474] pci_bus 0000:00: root bus resource [bus 00-7f]
[    2.473966] PCI: bus0: Fast back to back transfers enabled
[    2.479923] UBI: auto-attach mtd4
[    2.483240] ubi0: attaching mtd4
[    2.621521] ubi0: scanning is finished
[    2.635909] ubi0: attached mtd4 (name "ubi", size 114 MiB)
[    2.641382] ubi0: PEB size: 131072 bytes (128 KiB), LEB size: 129024 bytes
[    2.648284] ubi0: min./max. I/O unit sizes: 2048/2048, sub-page size 512
[    2.655001] ubi0: VID header offset: 512 (aligned 512), data offset: 2048
[    2.661760] ubi0: good PEBs: 912, bad PEBs: 0, corrupted PEBs: 0
[    2.667776] ubi0: user volume: 2, internal volumes: 1, max. volumes count: 128
[    2.675002] ubi0: max/mean erase counter: 4/2, WL threshold: 4096, image sequence number: 0
[    2.683317] ubi0: available PEBs: 0, total reserved PEBs: 912, PEBs reserved for bad PEB handling: 20
[    2.692595] ubi0: background thread "ubi_bgt0d" started, PID 43
[    2.693964] block ubiblock0_0: created from ubi0:0(rootfs)
[    2.704066] ubiblock: device ubiblock0_0 (rootfs) set to be root filesystem
[    2.711050] hctosys: unable to open rtc device (rtc0)
[    2.723146] VFS: Mounted root (squashfs filesystem) readonly on device 254:0.
[    2.732464] Freeing unused kernel memory: 1024K
[    3.127733] init: Console is alive
[    3.789790] kmodloader: loading kernel modules from /etc/modules-boot.d/*
[    3.877826] usbcore: registered new interface driver usbfs
[    3.883376] usbcore: registered new interface driver hub
[    3.888875] usbcore: registered new device driver usb
[    3.895206] Button Hotplug driver version 0.4.1
[    3.901844] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[    3.909632] ehci-platform: EHCI generic platform driver
[    4.124943] oxnas-ehci 40200100.ehci: EHCI Host Controller
[    4.130467] oxnas-ehci 40200100.ehci: new USB bus registered, assigned bus number 1
[    4.138767] oxnas-ehci 40200100.ehci: irq 52, io mem 0x40200100
[    4.164904] oxnas-ehci 40200100.ehci: USB 2.0 started, EHCI 1.00
[    4.172111] hub 1-0:1.0: USB hub found
[    4.176023] hub 1-0:1.0: 2 ports detected
[    4.183590] kmodloader: done loading kernel modules from /etc/modules-boot.d/*
[    4.198504] init: - preinit -
[    4.575040] usb 1-1: new high-speed USB device number 2 using oxnas-ehci
[    4.798261] random: procd: uninitialized urandom read (4 bytes read)
[    4.798318] hub 1-1:1.0: USB hub found
[    4.808975] hub 1-1:1.0: 4 ports detected
[    4.907594] random: jshn: uninitialized urandom read (4 bytes read)
[    4.966515] random: jshn: uninitialized urandom read (4 bytes read)
[    5.038046] RTL8211DN Gigabit Ethernet stmmac-0:00: attached PHY driver [RTL8211DN Gigabit Ethernet] (mii_bus:phy_addr=stmmac-0:00, irq=POLL)
[    5.064985] oxnas-dwmac 40400000.ethernet eth0: IEEE 1588-2008 Advanced Timestamp supported
[    5.073582] oxnas-dwmac 40400000.ethernet eth0: registered PTP clock
[    5.082071] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
Press the [f] key and hit [enter] to enter failsafe mode
Press the [1], [2], [3] or [4] key and hit [enter] to select the debug level
[    8.246323] oxnas-dwmac 40400000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx
[    8.254778] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[    8.377571] mount_root: loading kmods from internal overlay
[    8.403809] kmodloader: loading kernel modules from //etc/modules-boot.d/*
[    8.412070] kmodloader: done loading kernel modules from //etc/modules-boot.d/*
[    8.636935] __nand_correct_data: uncorrectable ECC error
[    8.642232] __nand_correct_data: uncorrectable ECC error
[    8.647608] print_req_error: I/O error, dev mtdblock1, sector 0
[    8.653621] __nand_correct_data: uncorrectable ECC error
[    8.658954] __nand_correct_data: uncorrectable ECC error
[    8.664250] print_req_error: I/O error, dev mtdblock1, sector 8
[    8.670295] __nand_correct_data: uncorrectable ECC error
[    8.675619] __nand_correct_data: uncorrectable ECC error
[    8.680919] print_req_error: I/O error, dev mtdblock1, sector 16
[    8.687045] __nand_correct_data: uncorrectable ECC error
[    8.692334] __nand_correct_data: uncorrectable ECC error
[    8.697666] print_req_error: I/O error, dev mtdblock1, sector 24
[    8.703928] __nand_correct_data: uncorrectable ECC error
[    8.709327] __nand_correct_data: uncorrectable ECC error
[    8.714636] print_req_error: I/O error, dev mtdblock1, sector 0
[    8.720535] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[    8.731066] __nand_correct_data: uncorrectable ECC error
[    8.736453] __nand_correct_data: uncorrectable ECC error
[    8.741762] print_req_error: I/O error, dev mtdblock1, sector 0
[    8.747660] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[    8.870617] UBIFS (ubi0:1): background thread "ubifs_bgt0_1" started, PID 110
[    8.911390] UBIFS (ubi0:1): recovery needed
[    9.084779] UBIFS (ubi0:1): recovery completed
[    9.090247] UBIFS (ubi0:1): UBIFS: mounted UBI device 0, volume 1, name "rootfs_data"
[    9.098119] UBIFS (ubi0:1): LEB size: 129024 bytes (126 KiB), min./max. I/O unit sizes: 2048 bytes/2048 bytes
[    9.108037] UBIFS (ubi0:1): FS size: 110057472 bytes (104 MiB, 853 LEBs), journal size 5548032 bytes (5 MiB, 43 LEBs)
[    9.118656] UBIFS (ubi0:1): reserved for root: 4952683 bytes (4836 KiB)
[    9.125314] UBIFS (ubi0:1): media format: w4/r0 (latest is w5/r0), UUID 206FE800-2F26-4118-85D4-1A3C371F3D21, small LPT model
[    9.137152] block: attempting to load /tmp/ubifs_cfg/upper/etc/config/fstab
[    9.144335] block: unable to load configuration (fstab: Entry not found)
[    9.151280] block: attempting to load /tmp/ubifs_cfg/etc/config/fstab
[    9.157987] block: unable to load configuration (fstab: Entry not found)
[    9.164866] block: attempting to load /etc/config/fstab
[    9.171701] block: unable to load configuration (fstab: Entry not found)
[    9.178583] block: no usable configuration
[    9.215057] UBIFS (ubi0:1): un-mount UBI device 0
[    9.219822] UBIFS (ubi0:1): background thread "ubifs_bgt0_1" stops
[    9.232752] UBIFS (ubi0:1): background thread "ubifs_bgt0_1" started, PID 111
[    9.317186] UBIFS (ubi0:1): UBIFS: mounted UBI device 0, volume 1, name "rootfs_data"
[    9.325844] UBIFS (ubi0:1): LEB size: 129024 bytes (126 KiB), min./max. I/O unit sizes: 2048 bytes/2048 bytes
[    9.335777] UBIFS (ubi0:1): FS size: 110057472 bytes (104 MiB, 853 LEBs), journal size 5548032 bytes (5 MiB, 43 LEBs)
[    9.346378] UBIFS (ubi0:1): reserved for root: 4952683 bytes (4836 KiB)
[    9.352967] UBIFS (ubi0:1): media format: w4/r0 (latest is w5/r0), UUID 206FE800-2F26-4118-85D4-1A3C371F3D21, small LPT model
[    9.405288] __nand_correct_data: uncorrectable ECC error
[    9.410588] __nand_correct_data: uncorrectable ECC error
[    9.415997] print_req_error: I/O error, dev mtdblock1, sector 0
[    9.422016] __nand_correct_data: uncorrectable ECC error
[    9.427371] __nand_correct_data: uncorrectable ECC error
[    9.432673] print_req_error: I/O error, dev mtdblock1, sector 8
[    9.438735] __nand_correct_data: uncorrectable ECC error
[    9.444024] __nand_correct_data: uncorrectable ECC error
[    9.449359] print_req_error: I/O error, dev mtdblock1, sector 16
[    9.455485] __nand_correct_data: uncorrectable ECC error
[    9.460771] __nand_correct_data: uncorrectable ECC error
[    9.466104] print_req_error: I/O error, dev mtdblock1, sector 24
[    9.472404] __nand_correct_data: uncorrectable ECC error
[    9.477765] __nand_correct_data: uncorrectable ECC error
[    9.483077] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[    9.493611] __nand_correct_data: uncorrectable ECC error
[    9.498997] __nand_correct_data: uncorrectable ECC error
[    9.504307] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[    9.624294] block: attempting to load /tmp/ubifs_cfg/upper/etc/config/fstab
[    9.631595] block: unable to load configuration (fstab: Entry not found)
[    9.638533] block: attempting to load /tmp/ubifs_cfg/etc/config/fstab
[    9.645327] block: unable to load configuration (fstab: Entry not found)
[    9.652142] block: attempting to load /etc/config/fstab
[    9.657789] block: unable to load configuration (fstab: Entry not found)
[    9.664586] block: no usable configuration
[    9.716390] mount_root: overlay filesystem has not been fully initialized yet
[    9.724160] mount_root: switching to ubifs overlay
[    9.751971] urandom-seed: Seed file not found (/etc/urandom.seed)
[    9.864468] procd: - early -
[   10.566374] procd: - ubus -
[   10.633364] urandom_read: 1 callbacks suppressed
[   10.633374] random: ubusd: uninitialized urandom read (4 bytes read)
[   10.645365] random: ubusd: uninitialized urandom read (4 bytes read)
[   10.652226] random: ubusd: uninitialized urandom read (4 bytes read)
[   10.660259] procd: - init -
Please press Enter to activate this console.
[   11.398266] urngd: v1.0.2 started.
[   11.434206] kmodloader: loading kernel modules from /etc/modules.d/*
[   11.460395] Loading modules backported from Linux version v4.19.120-0-gfdc072324f3c
[   11.468142] Backport generated by backports.git v4.19.120-1-0-g60c3a249
[   11.490273] nf_conntrack version 0.5.0 (2048 buckets, 8192 max)
[   11.531233] random: crng init done
[   11.534650] random: 3 urandom warning(s) missed due to ratelimiting
[   11.604254] xt_time: kernel timezone is -0000
[   11.637250] ip_tables: (C) 2000-2006 Netfilter Core Team
[   11.704535] kmodloader: done loading kernel modules from /etc/modules.d/*
[   15.339758] __nand_correct_data: uncorrectable ECC error
[   15.345118] __nand_correct_data: uncorrectable ECC error
[   15.350423] print_req_error: 2 callbacks suppressed
[   15.350433] print_req_error: I/O error, dev mtdblock1, sector 0
[   15.361587] __nand_correct_data: uncorrectable ECC error
[   15.366973] __nand_correct_data: uncorrectable ECC error
[   15.372280] print_req_error: I/O error, dev mtdblock1, sector 0
[   15.378565] __nand_correct_data: uncorrectable ECC error
[   15.383861] __nand_correct_data: uncorrectable ECC error
[   15.389253] print_req_error: I/O error, dev mtdblock1, sector 0
[   35.337344] __nand_correct_data: uncorrectable ECC error
[   35.342656] __nand_correct_data: uncorrectable ECC error
[   35.348088] print_req_error: I/O error, dev mtdblock1, sector 0
[   35.354109] __nand_correct_data: uncorrectable ECC error
[   35.359457] __nand_correct_data: uncorrectable ECC error
[   35.364766] print_req_error: I/O error, dev mtdblock1, sector 8
[   35.370818] __nand_correct_data: uncorrectable ECC error
[   35.376156] __nand_correct_data: uncorrectable ECC error
[   35.381452] print_req_error: I/O error, dev mtdblock1, sector 16
[   35.387607] __nand_correct_data: uncorrectable ECC error
[   35.392901] __nand_correct_data: uncorrectable ECC error
[   35.398292] print_req_error: I/O error, dev mtdblock1, sector 24
[   35.429365] __nand_correct_data: uncorrectable ECC error
[   35.434675] __nand_correct_data: uncorrectable ECC error
[   35.440161] print_req_error: I/O error, dev mtdblock1, sector 0
[   35.446074] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[   35.477401] __nand_correct_data: uncorrectable ECC error
[   35.482703] __nand_correct_data: uncorrectable ECC error
[   35.488115] print_req_error: I/O error, dev mtdblock1, sector 0
[   35.494016] Buffer I/O error on dev mtdblock1, logical block 0, async page read
[   37.145236] RTL8211DN Gigabit Ethernet stmmac-0:00: attached PHY driver [RTL8211DN Gigabit Ethernet] (mii_bus:phy_addr=stmmac-0:00, irq=POLL)
[   37.171432] oxnas-dwmac 40400000.ethernet eth0: IEEE 1588-2008 Advanced Timestamp supported
[   37.180272] oxnas-dwmac 40400000.ethernet eth0: registered PTP clock
[   37.196454] br-lan: port 1(eth0) entered blocking state
[   37.201681] br-lan: port 1(eth0) entered disabled state
[   37.207621] device eth0 entered promiscuous mode
[   37.217190] IPv6: ADDRCONF(NETDEV_UP): br-lan: link is not ready
[   40.315840] oxnas-dwmac 40400000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx
[   40.324300] br-lan: port 1(eth0) entered blocking state
[   40.329592] br-lan: port 1(eth0) entered forwarding state
[   40.336929] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready
 


BusyBox v1.30.1 () built-in shell (ash)

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 -----------------------------------------------------
 OpenWrt 19.07.3, r11063-85e04e9f46
 -----------------------------------------------------
=== WARNING! =====================================
There is no root password defined on this device!
Use the "passwd" command to set up a new password
in order to prevent unauthorized SSH logins.
--------------------------------------------------
root@OpenWrt:/# 

Most probable explanation would be hardware failure. NAND is known to wear out quicker than NOR after all.

If you had used a search engine you'd have found stuff like this:

https://openwrt.ebilan.co.uk/viewtopic.php?f=7&t=133#p1022

Your "errors" are related to the first few sectors, which might have been written without ECC checksums. My guess that the errors are harmless.

You might read this:
https://openwrt.org/docs/techref/flash#innocent_mtdblock_io_errors

One may encounter syslog messages that can safely be ignored. These messages are like

print_req_error: I/O error, dev mtdblock1, sector 0

https://bugs.openwrt.org/index.php?do=details&task_id=1871

Reason for closing: Not a bug
Additional comments about closing:

The first few blocks of a NAND flash are guaranteed good to ensure that a bootloader stored there can never get corrupted, so it will get written without valid ECC data (the SoC won't check the ECC anyway).

When block-mount scans all block devices, it will try to read from those blocks, which are exposed as partitions, and the NAND driver will report failed ECC checks (the I/O errors in the log).

There is nothing wrong here in either way, and nothing we can really do to prevent it.

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