Thank you for reporting. I'm sorry that I can't test myself, I don't have the device presently.
EDIT : something pop out my mind. You did perform a sysupgrade, so starting from a previous OpenWrt ?
Last time I did this, back in february, I also experimented a pseudo-bricked device : no IP, no response. I used the reset key while booting, and after the device responded. I restored Linksys OEM on a partition.
Flashing old versions using sysupgrade works flawlessly: this happens only when flashing newer builds...
Hi @clauded @badulesia
I am having the same problem on my MR8300 too on the last few snapshot builds too. I tried this over a period of 4-5 days and finally filed a bug report. Thats the one mentioned in this thread too.
According to the issue mentioned above, it looks like some nftables related issue. You can read through it.
Similar problem happening on Belkin RT3200.
It would be interesting if someone could log the serial output while booting.
I asked for that in the github issue that I filed as a bug. Someone there responded that he was noticing the issue was caused by nftables (the firewall package). I think thats not possible to know unless he can serial over and see the console output as the network is completely dead when these new snapshots load. I have asked for the log in that github issue.
I'm presently looking for a serial adapter to buy. That's a precious tool in case of issue. It's been a while since I used such thing (maybe ... previous century, lol). On images, I can see serial pins on the right side of the pcb. I'll give a try when I can.
Hi.
Ok I have a serial adapter, and I'll can have access to a MR8300 next week-end. Let's hope the issue will be solved in the meantime.
If not, I will try to grab a serial log while booting. I have just a silly question: can anyone show me a picture of the screws?
Here are also some infos.
EDIT: 3/31
I have now access to a MR8300.
I have installed the snapshot from 3/31 and indeed confirm that the issue is still here. Unfortunatly I can't go further. I have a serial adapter, I know how to use it, I have the UART pin scheme, the proper screwdrivers, but ... I only managed to unscrew 2/4. Both left have bad heads and I can't get rid of them. 
I hope any of these methods help! (I can't personally vouch for any of these methods)
https://machinehandyman.com/how-to-remove-a-broken-screw/
I already had a look on such things, but unfortunatly none applies on screws inside a hole. I'll bring back the router to home and try tougher method, even drilling.
Sorry to hear that 
Hi, I have the same problem.
It is described here:
I added my experience, the problem is still not resolved.
Hi.
Ok good news, I finaly got opened the MR8300!
I have booting serial logs of Linksys OEM, valid snapshot, and invalid snapshot. I will update the wiki with these logs, some pictures for opening the case, and UART pinout.
Here is a serial log of booting today (april 2nd) snapshot. As expected it fails.
I will keep the device for some time. If anyone wants to work on the matter I can try and log again.
Format: Log Type - Time(microsec) - Message - Optional Info
Log Type: B - Since Boot(Power On Reset), D - Delta, S - Statistic
S - QC_IMAGE_VERSION_STRING=BOOT.BF.3.1.1-00108
S - IMAGE_VARIANT_STRING=DAACANAZA
S - OEM_IMAGE_VERSION_STRING=CRM
S - Boot Config, 0x00000025
S - Reset status Config, 0x00000010
S - Core 0 Frequency, 0 MHz
B - 262 - PBL, Start
B - 1341 - bootable_media_detect_entry, Start
B - 2619 - bootable_media_detect_success, Start
B - 2633 - elf_loader_entry, Start
B - 4048 - auth_hash_seg_entry, Start
B - 6214 - auth_hash_seg_exit, Start
B - 71393 - elf_segs_hash_verify_entry, Start
B - 194114 - PBL, End
B - 194138 - SBL1, Start
B - 286316 - pm_device_init, Start
D - 7 - pm_device_init, Delta
B - 287814 - boot_flash_init, Start
D - 87496 - boot_flash_init, Delta
B - 379620 - boot_config_data_table_init, Start
D - 14027 - boot_config_data_table_init, Delta - (419 Bytes)
B - 396341 - clock_init, Start
D - 7560 - clock_init, Delta
B - 407340 - CDT version:2,Platform ID:8,Major ID:1,Minor ID:0,Subtype:6
B - 410752 - sbl1_ddr_set_params, Start
B - 415845 - cpr_init, Start
D - 2 - cpr_init, Delta
B - 420227 - Pre_DDR_clock_init, Start
D - 4 - Pre_DDR_clock_init, Delta
D - 13169 - sbl1_ddr_set_params, Delta
B - 433531 - pm_driver_init, Start
D - 2 - pm_driver_init, Delta
B - 504022 - sbl1_wait_for_ddr_training, Start
D - 28 - sbl1_wait_for_ddr_training, Delta
B - 520136 - Image Load, Start
D - 144031 - QSEE Image Loaded, Delta - (269176 Bytes)
B - 664599 - Image Load, Start
D - 2119 - SEC Image Loaded, Delta - (2048 Bytes)
B - 674744 - Image Load, Start
D - 187434 - APPSBL Image Loaded, Delta - (444135 Bytes)
B - 862574 - QSEE Execution, Start
D - 56 - QSEE Execution, Delta
B - 868796 - SBL1, End
D - 676660 - SBL1, Delta
S - Flash Throughput, 2084 KB/s (715778 Bytes, 343335 us)
S - DDR Frequency, 672 MHz
U-Boot 2012.07 [Chaos Calmer 15.05.1,r35193] (Sep 27 2018 - 09:37:31)
CBT U-Boot ver: 1.3.3
smem ram ptable found: ver: 1 len: 3
DRAM: 512 MiB
machid : 0x8010006
NAND: ID = 9590dac2
Vendor = c2
Device = da
ONFI device found
SF NAND unsupported id:ff:ff:ff:ffSF: Unsupported manufacturer ff
ipq_spi: SPI Flash not found (bus/cs/speed/mode) = (0/0/48000000/0)
256 MiB
MMC: qca_mmc: 0
PCI0 Link Intialized
In: serial
Out: serial
Err: serial
machid: 8010006
flash_type: 2
Net: MAC0 addr:0:3:7f:ba:db:ad
PHY ID1: 0x4d
PHY ID2: 0xd0b1
ipq40xx_ess_sw_init done
eth0
Updating boot_count ... done
Hit any key to stop autoboot: 0
Memory test start, banksize=0x2000000, data size=0x8000, test count per bank=64
Memory test end, lapsed time = 3 seconds
The test result is success
NAND read: device 0 offset 0x780000, size 0x500000
5242880 bytes read: OK
## Booting kernel from FIT Image at 84000000 ...
Using 'config@1' configuration
Trying 'kernel-1' kernel subimage
Description: ARM OpenWrt Linux-5.15.105
Type: Kernel Image
Compression: uncompressed
Data Start: 0x840000e4
Data Size: 3175064 Bytes = 3 MiB
Architecture: ARM
OS: Linux
Load Address: 0x80208000
Entry Point: 0x80208000
Hash algo: crc32
Hash value: fad15a7f
Hash algo: sha1
Hash value: 6f6fcccd91dd5ebef831024f9443cd90dc334ad5
Verifying Hash Integrity ... crc32+ sha1+ OK
## Flattened Device Tree from FIT Image at 84000000
Using 'config@1' configuration
Trying 'fdt-1' FDT blob subimage
Description: ARM OpenWrt linksys_mr8300 device tree blob
Type: Flat Device Tree
Compression: uncompressed
Data Start: 0x843074b4
Data Size: 18137 Bytes = 17.7 KiB
Architecture: ARM
Hash algo: crc32
Hash value: c1438877
Hash algo: sha1
Hash value: d3713708179a35075b1b68c428aaae8158e37d82
Verifying Hash Integrity ... crc32+ sha1+ OK
Booting using the fdt blob at 0x843074b4
Loading Kernel Image ... OK
OK
Loading Device Tree to 871e7000, end 871ee6d8 ... OK
Device nand2 not found!
eth0 MAC Address from ART is not valid
eth1 MAC Address from ART is not valid
Using machid 0x8010006 from environment
Starting kernel ...
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Linux version 5.15.105 (builder@buildhost) (arm-openwrt-linux-muslgnueabi-gcc (OpenWrt GCC 12.2.0 r22480-18d516a649) 12.2.0, GNU ld (GNU Binutils) 2.40.0) #0 SMP Sun Apr 2 00:25:16 2023
[ 0.000000] CPU: ARMv7 Processor [410fc075] revision 5 (ARMv7), cr=10c5387d
[ 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: Linksys MR8300 (Dallas)
[ 0.000000] Memory policy: Data cache writealloc
[ 0.000000] Zone ranges:
[ 0.000000] Normal [mem 0x0000000080000000-0x000000009fffffff]
[ 0.000000] HighMem empty
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000080000000-0x0000000087dfffff]
[ 0.000000] node 0: [mem 0x0000000087e00000-0x0000000087ffffff]
[ 0.000000] node 0: [mem 0x0000000088000000-0x000000009fffffff]
[ 0.000000] Initmem setup node 0 [mem 0x0000000080000000-0x000000009fffffff]
[ 0.000000] percpu: Embedded 12 pages/cpu s16588 r8192 d24372 u49152
[ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 129920
[ 0.000000] Kernel command line: init=/sbin/init rootfstype=ubifs ubi.mtd=11,2048 root=ubi0:ubifs rootwait rw root=/dev/ubiblock0_0 rootfstype=squashfs ro
[ 0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes, linear)
[ 0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes, linear)
[ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[ 0.000000] Memory: 505828K/524288K available (6825K kernel code, 610K rwdata, 1712K rodata, 1024K init, 247K bss, 18460K reserved, 0K cma-reserved, 0K highmem)
[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[ 0.000000] rcu: Hierarchical RCU implementation.
[ 0.000000] Tracing variant of Tasks RCU enabled.
[ 0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
[ 0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
[ 0.000000] arch_timer: cp15 timer(s) running at 48.00MHz (virt).
[ 0.000000] clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0xb11fd3bfb, max_idle_ns: 440795203732 ns
[ 0.000001] sched_clock: 56 bits at 48MHz, resolution 20ns, wraps every 4398046511096ns
[ 0.000026] Switching to timer-based delay loop, resolution 20ns
[ 0.000337] Calibrating delay loop (skipped), value calculated using timer frequency.. 96.00 BogoMIPS (lpj=480000)
[ 0.000367] pid_max: default: 32768 minimum: 301
[ 0.000606] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
[ 0.000633] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
[ 0.001673] CPU: Testing write buffer coherency: ok
[ 0.002060] qcom_scm: convention: smc legacy
[ 0.003202] Setting up static identity map for 0x80300000 - 0x8030003c
[ 0.003381] rcu: Hierarchical SRCU implementation.
[ 0.003654] dyndbg: Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build
[ 0.004009] smp: Bringing up secondary CPUs ...
[ 0.007401] smp: Brought up 1 node, 4 CPUs
[ 0.007437] SMP: Total of 4 processors activated (384.00 BogoMIPS).
[ 0.007454] CPU: All CPU(s) started in SVC mode.
[ 0.012891] VFP support v0.3: implementor 41 architecture 2 part 30 variant 7 rev 5
[ 0.013062] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[ 0.013095] futex hash table entries: 1024 (order: 4, 65536 bytes, linear)
[ 0.013374] pinctrl core: initialized pinctrl subsystem
[ 0.015099] NET: Registered PF_NETLINK/PF_ROUTE protocol family
[ 0.015535] DMA: preallocated 256 KiB pool for atomic coherent allocations
[ 0.016696] thermal_sys: Registered thermal governor 'step_wise'
[ 0.017128] cpuidle: using governor ladder
[ 0.017193] cpuidle: using governor menu
[ 0.044702] cryptd: max_cpu_qlen set to 1000
[ 0.049495] usbcore: registered new interface driver usbfs
[ 0.049575] usbcore: registered new interface driver hub
[ 0.049638] usbcore: registered new device driver usb
[ 0.049693] pps_core: LinuxPPS API ver. 1 registered
[ 0.049705] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it>
[ 0.049735] PTP clock support registered
[ 0.052152] clocksource: Switched to clocksource arch_sys_counter
[ 0.053125] NET: Registered PF_INET protocol family
[ 0.053369] IP idents hash table entries: 8192 (order: 4, 65536 bytes, linear)
[ 0.054401] tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 6144 bytes, linear)
[ 0.054456] Table-perturb hash table entries: 65536 (order: 6, 262144 bytes, linear)
[ 0.054478] TCP established hash table entries: 4096 (order: 2, 16384 bytes, linear)
[ 0.054541] TCP bind hash table entries: 4096 (order: 3, 32768 bytes, linear)
[ 0.054636] TCP: Hash tables configured (established 4096 bind 4096)
[ 0.054754] UDP hash table entries: 256 (order: 1, 8192 bytes, linear)
[ 0.054804] UDP-Lite hash table entries: 256 (order: 1, 8192 bytes, linear)
[ 0.055078] NET: Registered PF_UNIX/PF_LOCAL protocol family
[ 0.055135] PCI: CLS 0 bytes, default 64
[ 0.057271] workingset: timestamp_bits=14 max_order=17 bucket_order=3
[ 0.062509] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 0.062553] jffs2: version 2.2 (NAND) (SUMMARY) (LZMA) (RTIME) (CMODE_PRIORITY) (c) 2001-2006 Red Hat, Inc.
[ 0.195448] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 248)
[ 0.198258] qcom-pcie 40000000.pci: host bridge /soc/pci@40000000 ranges:
[ 0.198335] qcom-pcie 40000000.pci: IO 0x0040200000..0x00402fffff -> 0x0040200000
[ 0.198371] qcom-pcie 40000000.pci: MEM 0x0040300000..0x0040ffffff -> 0x0040300000
[ 0.373737] qcom-pcie 40000000.pci: iATU unroll: disabled
[ 0.373768] qcom-pcie 40000000.pci: Detected iATU regions: 32 outbound, 8 inbound
[ 0.473869] qcom-pcie 40000000.pci: Link up
[ 0.474042] qcom-pcie 40000000.pci: PCI host bridge to bus 0000:00
[ 0.474064] pci_bus 0000:00: root bus resource [bus 00-ff]
[ 0.474090] pci_bus 0000:00: root bus resource [io 0x0000-0xfffff] (bus address [0x40200000-0x402fffff])
[ 0.474110] pci_bus 0000:00: root bus resource [mem 0x40300000-0x40ffffff]
[ 0.474166] pci 0000:00:00.0: [17cb:1001] type 01 class 0x060400
[ 0.474202] pci 0000:00:00.0: reg 0x10: [mem 0x00000000-0x00000fff]
[ 0.474279] pci 0000:00:00.0: PME# supported from D0 D3hot
[ 0.475854] PCI: bus0: Fast back to back transfers disabled
[ 0.476137] pci 0000:01:00.0: [168c:0056] type 00 class 0x028000
[ 0.476275] pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x001fffff 64bit]
[ 0.476857] pci 0000:01:00.0: PME# supported from D0 D3hot
[ 0.478568] PCI: bus1: Fast back to back transfers disabled
[ 0.478618] pci 0000:00:00.0: BAR 8: assigned [mem 0x40400000-0x405fffff]
[ 0.478644] pci 0000:00:00.0: BAR 0: assigned [mem 0x40300000-0x40300fff]
[ 0.478669] pci 0000:01:00.0: BAR 0: assigned [mem 0x40400000-0x405fffff 64bit]
[ 0.478741] pci 0000:00:00.0: PCI bridge to [bus 01-ff]
[ 0.478763] pci 0000:00:00.0: bridge window [mem 0x40400000-0x405fffff]
[ 0.481688] pcieport 0000:00:00.0: AER: enabled with IRQ 102
[ 0.483882] bam-dma-engine 8e04000.dma: num-channels unspecified in dt
[ 0.483911] bam-dma-engine 8e04000.dma: num-ees unspecified in dt
[ 0.485293] tcsr 1949000.tcsr: setting wifi_glb_cfg = 41000000
[ 0.485414] tcsr 194b000.tcsr: setting usb hs phy mode select = e700e7
[ 0.485516] tcsr 1953000.ess_tcsr: setting ess interface select = 0
[ 0.485612] tcsr 1957000.tcsr: setting wifi_noc_memtype_m0_m2 = 2222222
[ 0.485936] Serial: 8250/16550 driver, 16 ports, IRQ sharing enabled
[ 0.487768] msm_serial 78af000.serial: msm_serial: detected port #0
[ 0.487820] msm_serial 78af000.serial: uartclk = 1843200
[ 0.487881] 78af000.serial: ttyMSM0 at MMIO 0x78af000 (irq = 32, base_baud = 115200) is a MSM
[ 0.487917] msm_serial: console setup on port #0
[ 1.204522] printk: console [ttyMSM0] enabled
[ 1.209672] msm_serial: driver initialized
[ 1.218816] loop: module loaded
[ 1.220462] nand: device found, Manufacturer ID: 0xc2, Chip ID: 0xda
[ 1.220779] nand: Macronix MX30LF2G18AC
[ 1.227422] nand: 256 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64
[ 1.230964] Block protection check failed
[ 1.238680] 16 fixed-partitions partitions found on MTD device qcom_nand.0
[ 1.242701] Creating 16 MTD partitions on "qcom_nand.0":
[ 1.249435] 0x000000000000-0x000000100000 : "sbl1"
[ 1.256539] 0x000000100000-0x000000200000 : "mibib"
[ 1.260904] 0x000000200000-0x000000300000 : "qsee"
[ 1.265719] 0x000000300000-0x000000380000 : "cdt"
[ 1.270079] 0x000000380000-0x000000400000 : "appsblenv"
[ 1.274897] 0x000000400000-0x000000480000 : "ART"
[ 1.279897] 0x000000480000-0x000000680000 : "appsbl"
[ 1.286131] 0x000000680000-0x000000700000 : "u_env"
[ 1.289802] 0x000000700000-0x000000740000 : "s_env"
[ 1.294247] 0x000000740000-0x000000780000 : "devinfo"
[ 1.299019] 0x000000780000-0x000005f80000 : "kernel"
[ 1.382415] 0x000000c80000-0x000005f80000 : "rootfs"
[ 1.456732] mtd: setting mtd11 (rootfs) as root device
[ 1.457079] mtdsplit: no squashfs found in "rootfs"
[ 1.460797] 0x000005f80000-0x00000b780000 : "alt_kernel"
[ 1.544294] 0x000006480000-0x00000b780000 : "alt_rootfs"
[ 1.618206] 0x00000b780000-0x00000b880000 : "sysdiag"
[ 1.619647] 0x00000b880000-0x00000ff00000 : "syscfg"
[ 1.738703] i2c_dev: i2c /dev entries driver
[ 1.740541] sdhci: Secure Digital Host Controller Interface driver
[ 1.742055] sdhci: Copyright(c) Pierre Ossman
[ 1.748090] sdhci-pltfm: SDHCI platform and OF driver helper
[ 1.756288] NET: Registered PF_INET6 protocol family
[ 1.759832] Segment Routing with IPv6
[ 1.763292] In-situ OAM (IOAM) with IPv6
[ 1.766809] NET: Registered PF_PACKET protocol family
[ 1.770775] bridge: filtering via arp/ip/ip6tables is no longer available by default. Update your scripts to load br_netfilter if you need this.
[ 1.775927] 8021q: 802.1Q VLAN Support v1.8
[ 1.788881] Registering SWP/SWPB emulation handler
[ 1.805025] qca8k-ipq4019 c000000.switch: configuring for fixed/internal link mode
[ 1.805281] qca8k-ipq4019 c000000.switch: Link is Up - 1Gbps/Full - flow control rx/tx
[ 1.897039] qca8k-ipq4019 c000000.switch lan1 (uninitialized): PHY [90000.mdio-1:00] driver [Qualcomm QCA8075] (irq=POLL)
[ 1.986517] qca8k-ipq4019 c000000.switch lan2 (uninitialized): PHY [90000.mdio-1:01] driver [Qualcomm QCA8075] (irq=POLL)
[ 2.077124] qca8k-ipq4019 c000000.switch lan3 (uninitialized): PHY [90000.mdio-1:02] driver [Qualcomm QCA8075] (irq=POLL)
[ 2.167065] qca8k-ipq4019 c000000.switch lan4 (uninitialized): PHY [90000.mdio-1:03] driver [Qualcomm QCA8075] (irq=POLL)
[ 2.258816] qca8k-ipq4019 c000000.switch wan (uninitialized): PHY [90000.mdio-1:04] driver [Qualcomm QCA8075] (irq=POLL)
[ 2.269839] DSA: tree 0 setup
[ 2.273568] ubi0: attaching mtd11
[ 2.273612] ubi0 error: ubi_attach_mtd_dev: VID header offset 2048 too large.
[ ▒[ 2.284388] Waiting for root device /dev/ubiblock0_0...
Hi again.
I have update the wiki with infos but I don't have enought rights to add pictures of opening case, PCB and UART.
I've updated the Github ticket with your additional info.
Great 
Apparently the error lies in the detection of mtd11.
[ 2.273568] ubi0: attaching mtd11
[ 2.273612] ubi0 error: ubi_attach_mtd_dev: VID header offset 2048 too large.
Hi
I have encountered this problem using the Master snapshot yesterday on my MR8300 (I have set the fw_setenv kernsize 500000)
Using a Debian 11 build system, I also noticed that the 22.03.x snapshot r20090 stopped booting with the 5.10.176 kernel
But the 22.03.x snapshot r20071 still works with the 5.10.168 kernel
Maybe related?
Hi.
Good idea to have tested this. On Github, @clauded posted this link
https://lore.kernel.org/lkml/20230306013308.3884777-1-chengzhihao1@huawei.com/t/
and suggested that it may be a recent kernel modification. Once that modification has been merged, it may bugs both 5.10 and 5.15 kernels. We already know that 5.15 snapshots don't boot, so there is now a possibility that the next 22.03.4 won't boot either.
I created the bug
Perhaps consider closing the duplicate in favour of adding information to the first issue opened.