我是新手，刚刚入手 BPI-M2 Ultra 板子。
发现使用sd卡启动 openwrt 映像时，有无限重启的现象。由于刚上手，不知从何下手，请高手指点一二，我应该从哪个方向去调查？
过程如下：
按照 wiki 指引（ 香蕉派 BPI-M2 Ultra - Banana Pi Wiki (banana-pi.org)），
参照 OpenWRT Linux 章节，从 openwrt 官网下载img （openwrt-sunxi-cortexa7-sinovoip_bananapi-m2-ultra-ext4-sdcard.img.gz），下载页面如下：
Index of /snapshots/targets/sunxi/cortexa7/
按照 wiki 中的烧录方案，我把上面的 img （9m大小）成功烧录至sd卡。然后把sd卡插入 BPI-M2 Ultra 板块中，接上串口上电启动。
在串口中看到，linux 内核开始加载，并在1.3s左右系统自动重启，重新执行 u-Boot 过程。串口日志贴在下边：
U-Boot SPL 2020.04-OpenWrt-r21791-c03e458c86 (Jan 13 2023 - 21:34:16 +0000)
DRAM: 2048 MiB
Trying to boot from MMC1
U-Boot 2020.04-OpenWrt-r21791-c03e458c86 (Jan 13 2023 - 21:34:16 +0000) Allwinner Technology
CPU: Allwinner R40 (SUN8I 1701)
Model: Banana Pi BPI-M2-Ultra
I2C: ready
DRAM: 2 GiB
MMC: Device ‘mmc@1c11000’: seq 1 is in use by ‘mmc@1c10000’
mmc@1c0f000: 0, mmc@1c10000: 2, mmc@1c11000: 1
Loading Environment from FAT… Unable to use mmc 1:0… In: serial@1c28000
Out: serial@1c28000
Err: serial@1c28000
Net: phy interface7
eth0: ethernet@1c50000
starting USB…
Bus usb@1c19000: failed to get usb phy
Port not available.
Bus usb@1c19400: failed to get usb phy
Port not available.
Bus usb@1c1c000: failed to get usb phy
Port not available.
Bus usb@1c1c400: failed to get usb phy
Port not available.
Hit any key to stop autoboot: 0
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1…
Found U-Boot script /boot.scr
475 bytes read in 1 ms (463.9 KiB/s)
Executing script at 43100000
3741352 bytes read in 169 ms (21.1 MiB/s)
22961 bytes read in 3 ms (7.3 MiB/s)
Booting kernel from Legacy Image at 42000000 …
Image Name: ARM OpenWrt Linux-5.15.87
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 3741288 Bytes = 3.6 MiB
Load Address: 40008000
Entry Point: 40008000
Verifying Checksum … OK
Flattened Device Tree blob at 43000000
Booting using the fdt blob at 0x43000000
Loading Kernel Image
Using Device Tree in place at 43000000, end 430089b0
Starting kernel …
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Linux version 5.15.87 (builder@buildhost) (arm-openwrt-linux-muslgnueabi-gcc (OpenWrt GCC 12.2.0 r21791-c03e458c86) 12.2.0, GNU ld (GNU Binutils) 2.39) #0 SMP Fri Jan 13 21:34:16 2023
[ 0.000000] CPU: ARMv7 Processor [410fc075] revision 5 (ARMv7), cr=30c5387d
[ 0.000000] CPU: div instructions available: patching division code
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[ 0.000000] OF: fdt: Machine model: Banana Pi BPI-M2-Ultra
[ 0.000000] Memory policy: Data cache writealloc
[ 0.000000] Zone ranges:
[ 0.000000] Normal [mem 0x0000000040000000-0x000000006fffffff]
[ 0.000000] HighMem [mem 0x0000000070000000-0x00000000bfffffff]
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000040000000-0x00000000bfffffff]
[ 0.000000] Initmem setup node 0 [mem 0x0000000040000000-0x00000000bfffffff]
[ 0.000000] psci: probing for conduit method from DT.
[ 0.000000] psci: Using PSCI v0.1 Function IDs from DT
[ 0.000000] percpu: Embedded 12 pages/cpu s16588 r8192 d24372 u49152
[ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 522560
[ 0.000000] Kernel command line: console=ttyS0,115200 earlyprintk root=PARTUUID=5452574f-02 rootwait
[ 0.000000] Unknown kernel command line parameters “earlyprintk”, will be passed to user space.
[ 0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes, linear)
[ 0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes, linear)
[ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[ 0.000000] Memory: 2062160K/2097152K available (7958K kernel code, 840K rwdata, 2108K rodata, 2048K init, 263K bss, 34992K reserved, 0K cma-reserved, 1310708K highmem)
[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[ 0.000000] rcu: Hierarchical RCU implementation.
[ 0.000000] rcu: RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4.
[ 0.000000] Tracing variant of Tasks RCU enabled.
[ 0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
[ 0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=4
[ 0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
[ 0.000000] GIC: Using split EOI/Deactivate mode
[ 0.000000] clocksource: timer: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635851949 ns
[ 0.000000] arch_timer: cp15 timer(s) running at 24.00MHz (phys).
[ 0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x588fe9dc0, max_idle_ns: 440795202592 ns
[ 0.000001] sched_clock: 56 bits at 24MHz, resolution 41ns, wraps every 4398046511097ns
[ 0.000019] Switching to timer-based delay loop, resolution 41ns
[ 0.000192] Console: colour dummy device 80x30
[ 0.000258] Calibrating delay loop (skipped), value calculated using timer frequency… 48.00 BogoMIPS (lpj=240000)
[ 0.000279] pid_max: default: 32768 minimum: 301
[ 0.000492] Mount-cache hash table entries: 2048 (order: 1, 8192 bytes, linear)
[ 0.000518] Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes, linear)
[ 0.001409] CPU: Testing write buffer coherency: ok
[ 0.001778] /cpus/cpu@0 missing clock-frequency property
[ 0.001817] /cpus/cpu@1 missing clock-frequency property
[ 0.001838] /cpus/cpu@2 missing clock-frequency property
[ 0.001859] /cpus/cpu@3 missing clock-frequency property
[ 0.001873] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[ 0.002662] Setting up static identity map for 0x40200000 - 0x40200060
[ 0.002795] rcu: Hierarchical SRCU implementation.
[ 0.002970] dyndbg: Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build
[ 0.003363] smp: Bringing up secondary CPUs …
[ 0.014081] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
[ 0.024909] CPU2: thread -1, cpu 2, socket 0, mpidr 80000002
[ 0.035640] CPU3: thread -1, cpu 3, socket 0, mpidr 80000003
[ 0.035728] smp: Brought up 1 node, 4 CPUs
[ 0.035757] SMP: Total of 4 processors activated (192.00 BogoMIPS).
[ 0.035768] CPU: All CPU(s) started in HYP mode.
[ 0.035775] CPU: Virtualization extensions available.
[ 0.041795] VFP support v0.3: implementor 41 architecture 2 part 30 variant 7 rev 5
[ 0.042023] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[ 0.042051] futex hash table entries: 1024 (order: 4, 65536 bytes, linear)
[ 0.042331] pinctrl core: initialized pinctrl subsystem
[ 0.043672] NET: Registered PF_NETLINK/PF_ROUTE protocol family
[ 0.043981] DMA: preallocated 256 KiB pool for atomic coherent allocations
[ 0.044942] thermal_sys: Registered thermal governor ‘step_wise’
[ 0.045203] No ATAGs?
[ 0.069418] SCSI subsystem initialized
[ 0.069855] usbcore: registered new interface driver usbfs
[ 0.069907] usbcore: registered new interface driver hub
[ 0.069953] usbcore: registered new device driver usb
[ 0.070190] pps_core: LinuxPPS API ver. 1 registered
[ 0.070200] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti [email protected]
[ 0.070223] PTP clock support registered
[ 0.070466] Advanced Linux Sound Architecture Driver Initialized.
[ 0.071622] clocksource: Switched to clocksource arch_sys_counter
[ 0.076074] NET: Registered PF_INET protocol family
[ 0.076313] IP idents hash table entries: 16384 (order: 5, 131072 bytes, linear)
[ 0.077424] tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 6144 bytes, linear)
[ 0.077466] Table-perturb hash table entries: 65536 (order: 6, 262144 bytes, linear)
[ 0.077488] TCP established hash table entries: 8192 (order: 3, 32768 bytes, linear)
[ 0.077563] TCP bind hash table entries: 8192 (order: 4, 65536 bytes, linear)
[ 0.077682] TCP: Hash tables configured (established 8192 bind 8192)
[ 0.077795] UDP hash table entries: 512 (order: 2, 16384 bytes, linear)
[ 0.077863] UDP-Lite hash table entries: 512 (order: 2, 16384 bytes, linear)
[ 0.078107] NET: Registered PF_UNIX/PF_LOCAL protocol family
[ 0.079144] workingset: timestamp_bits=14 max_order=19 bucket_order=5
[ 0.083802] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 0.083925] jffs2: version 2.2 (NAND) (SUMMARY) (LZMA) (RTIME) (CMODE_PRIORITY) (c) 2001-2006 Red Hat, Inc.
[ 0.085084] bounce: pool size: 64 pages
[ 0.085167] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 248)
[ 0.086789] sun4i-usb-phy 1c13400.phy: failed to get clock usb0_phy
[ 0.088904] sun4i-pinctrl 1c20800.pinctrl: supply vcc-pi not found, using dummy regulator
[ 0.102989] Serial: 8250/16550 driver, 16 ports, IRQ sharing enabled
[ 0.111500] loop: module loaded
[ 0.111948] Loading iSCSI transport class v2.0-870.
[ 0.116456] ehci_hcd: USB 2.0 ‘Enhanced’ Host Controller (EHCI) Driver
[ 0.116498] ehci-platform: EHCI generic platform driver
[ 0.117021] ohci_hcd: USB 1.1 ‘Open’ Host Controller (OHCI) Driver
[ 0.117067] ohci-platform: OHCI generic platform driver
[ 0.117608] usbcore: registered new interface driver usb-storage
[ 0.118163] mousedev: PS/2 mouse device common for all mice
[ 0.119582] sun6i-rtc 1c20400.rtc: registered as rtc0
[ 0.119659] sun6i-rtc 1c20400.rtc: setting system clock to 1970-01-01T00:00:12 UTC (12)
[ 0.119686] sun6i-rtc 1c20400.rtc: RTC enabled
[ 0.119911] i2c_dev: i2c /dev entries driver
[ 0.122072] sunxi-wdt 1c20c90.watchdog: Watchdog enabled (timeout=16 sec, nowayout=0)
[ 0.125102] NET: Registered PF_INET6 protocol family
[ 0.126243] Segment Routing with IPv6
[ 0.126312] In-situ OAM (IOAM) with IPv6
[ 0.126391] NET: Registered PF_PACKET protocol family
[ 0.126457] bridge: filtering via arp/ip/ip6tables is no longer available by default. Update your scripts to load br_netfilter if you need this.
[ 0.126631] can: controller area network core
[ 0.126776] NET: Registered PF_CAN protocol family
[ 0.126788] 8021q: 802.1Q VLAN Support v1.8
[ 0.126908] Registering SWP/SWPB emulation handler
[ 0.139955] sun4i-usb-phy 1c13400.phy: Couldn’t get regulator usb1_vbus… Deferring probe
[ 0.141943] sun4i-pinctrl 1c20800.pinctrl: supply vcc-pi not found, using dummy regulator
[ 0.143523] sun4i-pinctrl 1c20800.pinctrl: initialized sunXi PIO driver
[ 0.145601] sun4i-pinctrl 1c20800.pinctrl: supply vcc-pb not found, using dummy regulator
[ 0.146042] printk: console [ttyS0] disabled
[ 0.166284] 1c28000.serial: ttyS0 at MMIO 0x1c28000 (irq = 51, base_baud = 1500000) is a U6_16550A
[ 0.936252] printk: console [ttyS0] enabled
[ 0.941273] sun4i-pinctrl 1c20800.pinctrl: Couldn’t get bank PG regulator
[ 0.948113] sun4i-pinctrl 1c20800.pinctrl: request() failed for pin 198
[ 0.954739] sun4i-pinctrl 1c20800.pinctrl: pin-198 (1c28c00.serial) status -517
[ 0.962057] sun4i-pinctrl 1c20800.pinctrl: could not request pin 198 (PG6) from group PG6 on device 1c20800.pinctrl
[ 0.972589] dw-apb-uart 1c28c00.serial: Error applying setting, reverse things back
[ 0.980549] sun4i-pinctrl 1c20800.pinctrl: Couldn’t get bank PA regulator
[ 0.987353] sun4i-pinctrl 1c20800.pinctrl: request() failed for pin 0
[ 0.993801] sun4i-pinctrl 1c20800.pinctrl: pin-0 (1c50000.ethernet) status -517
[ 1.001104] sun4i-pinctrl 1c20800.pinctrl: could not request pin 0 (PA0) from group PA0 on device 1c20800.pinctrl
[ 1.011453] dwmac-sun8i 1c50000.ethernet: Error applying setting, reverse things back
[ 1.022233] axp20x-i2c 0-0034: AXP20x variant AXP221 found
[ 1.035123] input: axp20x-pek as /devices/platform/soc/1c2ac00.i2c/i2c-0/0-0034/axp221-pek/input/input0
[ 1.053726] vcc-3v3: supplied by regulator-dummy
[ 1.059547] vdd-cpu: supplied by regulator-dummy
[ 1.064881] vdd-sys: supplied by regulator-dummy
[ 1.070313] dcdc4: supplied by regulator-dummy
[ 1.075322] vcc-dram: supplied by regulator-dummy
[ 1.080269] vcc-gmac-phy: failed to get the current voltage: -EPROBE_DEFER
[ 1.087207] vcc-gmac-phy: supplied by vcc-3v3
[ 1.092404] dc5ldo: supplied by vcc-dram
[ 1.097020] aldo1: supplied by regulator-dummy
[ 1.102155] vcc-pa: supplied by regulator-dummy
[ 1.107222] avcc: supplied by regulator-dummy
[ 1.112846] eldo1: supplied by regulator-dummy
[ 1.117969] eldo2: supplied by regulator-dummy
[ 1.123147] vdd1v2-sata: supplied by regulator-dummy
[ 1.128635] vcc-wifi-io: Bringing 700000uV into 1800000-1800000uV
[ 1.135657] vcc-wifi-io: supplied by regulator-dummy
[ 1.141139] vcc-wifi: Bringing 700000uV into 3300000-3300000uV
[ 1.147325] vcc-wifi: supplied by regulator-dummy
[ 1.153019] vcc-wifi-2: Bringing 700000uV into 3300000-3300000uV
[ 1.159363] vcc-wifi-2: supplied by regulator-dummy
[ 1.165419] vdd2v5-sata: supplied by regulator-dummy
[ 1.170516] rtc_ldo: supplied by regulator-dummy
[ 1.175981] ldo_io0: supplied by regulator-dummy
[ 1.181241] ldo_io1: supplied by regulator-dummy
[ 1.186460] axp20x-i2c 0-0034: AXP20X driver loaded
[ 1.194130] sun4i-pinctrl 1c20800.pinctrl: supply vcc-ph not found, using dummy regulator
[ 1.202490] sunxi-mmc 1c0f000.mmc: Got CD GPIO
[ 1.204149] sunxi-mmc 1c10000.mmc: allocated mmc-pwrseq
[ 1.225570] 1c28c00.serial: ttyS1 at MMIO 0x1c28c00 (irq = 52, base_baud = 1500000) is a U6_16550A
[ 1.231634] sunxi-mmc 1c11000.mmc: initialized, max. request size: 2048 KB, uses new timings mode
[ 1.231855] sunxi-mmc 1c0f000.mmc: initialized, max. request size: 16384 KB, uses new timings mode
[ 1.235850] dwmac-sun8i 1c50000.ethernet: IRQ eth_wake_irq not found
[ 1.238441] sunxi-mmc 1c10000.mmc: initialized, max. request size: 16384 KB, uses new timings mode
[ 1.267686] dwmac-sun8i 1c50000.ethernet: IRQ eth_lpi not found
[ 1.273980] dwmac-sun8i 1c50000.ethernet: PTP uses main clock
[ 1.279757] dwmac-sun8i 1c50000.ethernet: Current syscon value is not the default 6 (expect 0)
[ 1.280819] mmc1: host does not support reading read-only switch, assuming write-enable
[ 1.296598] dwmac-sun8i 1c50000.ethernet: No HW DMA feature register supported
[ 1.299852] mmc1: new high speed SDHC card at address 0001
[ 1.303839] dwmac-sun8i 1c50000.ethernet: RX Checksum Offload Engine supported
[ 1.316553] dwmac-sun8i 1c50000.ethernet: COE Type 2
[ 1.317199] mmcblk1: mmc1:0001 SD16G 29.1 GiB
[ 1.321530] dwmac-sun8i 1c50000.ethernet: TX Checksum insertion supported
[ 1.327104] mmcblk1: p1 p2
[ 1.332761] dwmac-sun8i 1c50000.ethernet: Normal descriptors
[ 1.332769] dwmac-sun8i 1c50000.ethernet: Chain m
U-Boot SPL 2020.04-OpenWrt-r21791-c03e458c86 (Jan 13 2023 - 21:34:16 +0000)
DRAM: 2048 MiB
Trying to boot from MMC1
U-Boot 2020.04-OpenWrt-r21791-c03e458c86 (Jan 13 2023 - 21:34:16 +0000) Allwinner Technology
CPU: Allwinner R40 (SUN8I 1701)
Model: Banana Pi BPI-M2-Ultra
I2C: ready
DRAM: 2 GiB
MMC: Device ‘mmc@1c11000’: seq 1 is in use by ‘mmc@1c10000’
mmc@1c0f000: 0, mmc@1c10000: 2, mmc@1c11000: 1
Loading Environment from FAT… Unable to use mmc 1:0… In: serial@1c28000
Out: serial@1c28000
Err: serial@1c28000
Net: phy interface7
eth0: ethernet@1c50000
starting USB…
Bus usb@1c19000: failed to get usb phy
Port not available.
Bus usb@1c19400: failed to get usb phy
Port not available.
Bus usb@1c1c000: failed to get usb phy
Port not available.
Bus usb@1c1c400: failed to get usb phy
Port not available.
Hit any key to stop autoboot: 0
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1…
Found U-Boot script /boot.scr
475 bytes read in 1 ms (463.9 KiB/s)
Executing script at 43100000
3741352 bytes read in 169 ms (21.1 MiB/s)
22961 bytes read in 3 ms (7.3 MiB/s)
Booting kernel from Legacy Image at 42000000 …
Image Name: ARM OpenWrt Linux-5.15.87
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 3741288 Bytes = 3.6 MiB
Load Address: 40008000
Entry Point: 40008000
Verifying Checksum … OK
Flattened Device Tree blob at 43000000
Booting using the fdt blob at 0x43000000
Loading Kernel Image
Using Device Tree in place at 43000000, end 430089b0
Starting kernel …