eth0 servely drops packets

Due to high packet loss on BTT Pi v1.2 (exactly the same behavior as follows), I switched to BTT Pi2.

I am running the latest version of system on the BTT Pi2, namely the [CB2_Debian11_minimal_kernel4.19_20240619.img.xz](https://github.com/bigtreetech/CB2/releases/download/V1.0.5/CB2_Debian11_minimal_kernel4.19_20240619.img.xz)

I used Netplan to assign a static IP:
Netplan config files:
```
network:
version: 2
renderer: NetworkManager
ethernets:
eth0:
dhcp4: no
addresses: [192.168.1.199/24]
gateway4: 192.168.1.1
nameservers:
addresses: [192.168.1.1, 223.5.5.5]

```
And I am getting huge packet drops on eth0, the onboard Ethernet.
Here's some ping tests over the course of roughly 10 mins:

Pinging the BTT Pi2 (192.168.1.199) from my computer (192.168.1.5)

Pinging the main router (192.168.1.1, running OpenWRT, x86 Intel system) from BTT Pi2 (192.168.1.199)

Network topology: Main Router -> 2.5GbE Switch -> 2.5GbE Switch ->BTT Pi2

Here's some outputs of command lines:
```
root@Hachiroku:~# dmesg | grep -i eth
[ 0.000000] psci: probing for conduit method from DT.
[ 2.284113] rk_gmac-dwmac fe010000.ethernet: Looking up phy-supply from device tree
[ 2.284143] rk_gmac-dwmac fe010000.ethernet: phy regulator is not available yet, deferred probing
[ 2.286201] usbcore: registered new interface driver cdc_ether
[ 3.275477] rk_gmac-dwmac fe010000.ethernet: Looking up phy-supply from device tree
[ 3.275547] rk_gmac-dwmac fe010000.ethernet: Linked as a consumer to regulator.27
[ 3.275553] rk_gmac-dwmac fe010000.ethernet: clock input or output? (input).
[ 3.275558] rk_gmac-dwmac fe010000.ethernet: TX delay(0x19).
[ 3.275562] rk_gmac-dwmac fe010000.ethernet: RX delay(0x5).
[ 3.275569] rk_gmac-dwmac fe010000.ethernet: integrated PHY? (no).
[ 3.275603] rk_gmac-dwmac fe010000.ethernet: clock input from PHY
[ 3.280614] rk_gmac-dwmac fe010000.ethernet: init for RGMII
[ 3.280805] rk_gmac-dwmac fe010000.ethernet: User ID: 0x30, Synopsys ID: 0x51
[ 3.280812] rk_gmac-dwmac fe010000.ethernet: DWMAC4/5
[ 3.280817] rk_gmac-dwmac fe010000.ethernet: DMA HW capability register supported
[ 3.280821] rk_gmac-dwmac fe010000.ethernet: RX Checksum Offload Engine supported
[ 3.280823] rk_gmac-dwmac fe010000.ethernet: TX Checksum insertion supported
[ 3.280826] rk_gmac-dwmac fe010000.ethernet: Wake-Up On Lan supported
[ 3.280854] rk_gmac-dwmac fe010000.ethernet: TSO supported
[ 3.280857] rk_gmac-dwmac fe010000.ethernet: Enable RX Mitigation via HW Watchdog Timer
[ 3.280862] rk_gmac-dwmac fe010000.ethernet: TSO feature enabled
[ 3.420669] YT8531 Gigabit Ethernet stmmac-1:00: [phy_probe-1989] led_status_value normal
[ 12.854724] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 13.096759] YT8531 Gigabit Ethernet stmmac-1:00: attached PHY driver [YT8531 Gigabit Ethernet] (mii_bus:phy_addr=stmmac-1:00, irq=POLL)
[ 13.114158] rk_gmac-dwmac fe010000.ethernet eth0: No Safety Features support found
[ 13.114181] rk_gmac-dwmac fe010000.ethernet eth0: IEEE 1588-2008 Advanced Timestamp supported
[ 13.120794] rk_gmac-dwmac fe010000.ethernet eth0: registered PTP clock
[ 13.121532] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 16.173233] rk_gmac-dwmac fe010000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx
[ 16.173311] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 132.705917] rk_gmac-dwmac fe010000.ethernet eth0: Link is Down
[ 133.719396] rk_gmac-dwmac fe010000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx

```

```
root@Hachiroku:~# netstat -s
Ip:
Forwarding: 2
102780 total packets received
3 with invalid addresses
0 forwarded
0 incoming packets discarded
102403 incoming packets delivered
89739 requests sent out
42 dropped because of missing route
Icmp:
2241 ICMP messages received
0 input ICMP message failed
ICMP input histogram:
destination unreachable: 65
echo requests: 1500
echo replies: 676
2373 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 67
echo requests: 806
echo replies: 1500
IcmpMsg:
InType0: 676
InType3: 65
InType8: 1500
OutType0: 1500
OutType3: 67
OutType8: 806
Tcp:
85 active connection openings
74 passive connection openings
0 failed connection attempts
106 connection resets received
1 connections established
98993 segments received
174744 segments sent out
5887 segments retransmitted
0 bad segments received
88 resets sent
Udp:
1137 packets received
67 packets to unknown port received
0 packet receive errors
216 packets sent
0 receive buffer errors
0 send buffer errors
IgnoredMulti: 283
UdpLite:
TcpExt:
18 TCP sockets finished time wait in fast timer
323 delayed acks sent
20 delayed acks further delayed because of locked socket
Quick ack mode was activated 85 times
21899 packet headers predicted
22631 acknowledgments not containing data payload received
52355 predicted acknowledgments
TCPSackRecovery: 3850
1 congestion windows recovered without slow start after partial ack
TCPLostRetransmit: 795
3 timeouts in loss state
4767 fast retransmits
64 retransmits in slow start
TCPTimeouts: 607
TCPLossProbes: 467
TCPLossProbeRecovery: 238
TCPSackRecoveryFail: 414
TCPDSACKOldSent: 85
TCPDSACKRecv: 137
71 connections reset due to unexpected data
1 connections reset due to early user close
TCPDSACKIgnoredNoUndo: 42
TCPSpuriousRTOs: 1
TCPSackShifted: 1247
TCPSackMerged: 1873
TCPSackShiftFallback: 6872
TCPRcvCoalesce: 3628
TCPOFOQueue: 9
TCPSpuriousRtxHostQueues: 90
TCPAutoCorking: 3925
TCPFromZeroWindowAdv: 13
TCPToZeroWindowAdv: 13
TCPWantZeroWindowAdv: 81
TCPOrigDataSent: 158565
TCPACKSkippedSeq: 5
TCPWinProbe: 19
TCPDelivered: 158153
IpExt:
InMcastPkts: 790
OutMcastPkts: 126
InBcastPkts: 283
InOctets: 150789572
OutOctets: 299309607
InMcastOctets: 146236
OutMcastOctets: 34243
InBcastOctets: 114600
InNoECTPkts: 102846
```

```
root@Hachiroku:~# ethtool -S eth0
NIC statistics:
mmc_tx_octetcount_gb: 340174588
mmc_tx_framecount_gb: 331037
mmc_tx_broadcastframe_g: 0
mmc_tx_multicastframe_g: 0
mmc_tx_64_octets_gb: 0
mmc_tx_65_to_127_octets_gb: 0
mmc_tx_128_to_255_octets_gb: 0
mmc_tx_256_to_511_octets_gb: 0
mmc_tx_512_to_1023_octets_gb: 0
mmc_tx_1024_to_max_octets_gb: 0
mmc_tx_unicast_gb: 0
mmc_tx_multicast_gb: 0
mmc_tx_broadcast_gb: 0
mmc_tx_underflow_error: 0
mmc_tx_singlecol_g: 0
mmc_tx_multicol_g: 0
mmc_tx_deferred: 0
mmc_tx_latecol: 0
mmc_tx_exesscol: 0
mmc_tx_carrier_error: 0
mmc_tx_octetcount_g: 340174588
mmc_tx_framecount_g: 331037
mmc_tx_excessdef: 0
mmc_tx_pause_frame: 0
mmc_tx_vlan_frame_g: 0
mmc_rx_framecount_gb: 162558
mmc_rx_octetcount_gb: 13586448
mmc_rx_octetcount_g: 13586448
mmc_rx_broadcastframe_g: 0
mmc_rx_multicastframe_g: 3456
mmc_rx_crc_error: 0
mmc_rx_align_error: 0
mmc_rx_run_error: 0
mmc_rx_jabber_error: 0
mmc_rx_undersize_g: 0
mmc_rx_oversize_g: 0
mmc_rx_64_octets_gb: 0
mmc_rx_65_to_127_octets_gb: 0
mmc_rx_128_to_255_octets_gb: 0
mmc_rx_256_to_511_octets_gb: 0
mmc_rx_512_to_1023_octets_gb: 0
mmc_rx_1024_to_max_octets_gb: 0
mmc_rx_unicast_g: 0
mmc_rx_length_error: 0
mmc_rx_autofrangetype: 0
mmc_rx_pause_frames: 0
mmc_rx_fifo_overflow: 0
mmc_rx_vlan_frames_gb: 0
mmc_rx_watchdog_error: 0
mmc_rx_ipc_intr_mask: 1417958598
mmc_rx_ipc_intr: 0
mmc_rx_ipv4_gd: 158088
mmc_rx_ipv4_hderr: 800
mmc_rx_ipv4_nopay: 0
mmc_rx_ipv4_frag: 0
mmc_rx_ipv4_udsbl: 0
mmc_rx_ipv4_gd_octets: 0
mmc_rx_ipv4_hderr_octets: 267214
mmc_rx_ipv4_nopay_octets: 0
mmc_rx_ipv4_frag_octets: 0
mmc_rx_ipv4_udsbl_octets: 0
mmc_rx_ipv6_gd_octets: 0
mmc_rx_ipv6_hderr_octets: 0
mmc_rx_ipv6_nopay_octets: 0
mmc_rx_ipv6_gd: 870
mmc_rx_ipv6_hderr: 0
mmc_rx_ipv6_nopay: 0
mmc_rx_udp_gd: 0
mmc_rx_udp_err: 0
mmc_rx_tcp_gd: 0
mmc_rx_tcp_err: 0
mmc_rx_icmp_gd: 0
mmc_rx_icmp_err: 0
mmc_rx_udp_gd_octets: 0
mmc_rx_udp_err_octets: 0
mmc_rx_tcp_gd_octets: 0
mmc_rx_tcp_err_octets: 0
mmc_rx_icmp_gd_octets: 0
mmc_rx_icmp_err_octets: 0
tx_underflow: 0
tx_carrier: 0
tx_losscarrier: 0
vlan_tag: 0
tx_deferred: 0
tx_vlan: 0
tx_jabber: 0
tx_frame_flushed: 0
tx_payload_error: 0
tx_ip_header_error: 0
rx_desc: 0
sa_filter_fail: 0
overflow_error: 0
ipc_csum_error: 0
rx_collision: 0
rx_crc_errors: 0
dribbling_bit: 0
rx_length: 0
rx_mii: 0
rx_multicast: 0
rx_gmac_overflow: 0
rx_watchdog: 0
da_rx_filter_fail: 0
sa_rx_filter_fail: 0
rx_missed_cntr: 0
rx_overflow_cntr: 0
rx_vlan: 0
tx_undeflow_irq: 0
tx_process_stopped_irq: 0
tx_jabber_irq: 0
rx_overflow_irq: 0
rx_buf_unav_irq: 0
rx_process_stopped_irq: 0
rx_watchdog_irq: 0
tx_early_irq: 0
fatal_bus_error_irq: 0
rx_early_irq: 10105
threshold: 1
tx_pkt_n: 66908
rx_pkt_n: 81373
normal_irq_n: 103547
rx_normal_irq_n: 38111
napi_poll: 111900
tx_normal_irq_n: 65011
tx_clean: 111900
tx_set_ic_bit: 66908
irq_receive_pmt_irq_n: 0
mmc_tx_irq_n: 0
mmc_rx_irq_n: 0
mmc_rx_csum_offload_irq_n: 0
irq_tx_path_in_lpi_mode_n: 0
irq_tx_path_exit_lpi_mode_n: 0
irq_rx_path_in_lpi_mode_n: 3
irq_rx_path_exit_lpi_mode_n: 3
phy_eee_wakeup_error_n: 0
ip_hdr_err: 0
ip_payload_err: 0
ip_csum_bypassed: 1415
ipv4_pkt_rcvd: 79515
ipv6_pkt_rcvd: 443
no_ptp_rx_msg_type_ext: 81373
ptp_rx_msg_type_sync: 0
ptp_rx_msg_type_follow_up: 0
ptp_rx_msg_type_delay_req: 0
ptp_rx_msg_type_delay_resp: 0
ptp_rx_msg_type_pdelay_req: 0
ptp_rx_msg_type_pdelay_resp: 0
ptp_rx_msg_type_pdelay_follow_up: 0
ptp_rx_msg_type_announce: 0
ptp_rx_msg_type_management: 0
ptp_rx_msg_pkt_reserved_type: 0
ptp_frame_type: 0
ptp_ver: 0
timestamp_dropped: 0
av_pkt_rcvd: 0
av_tagged_pkt_rcvd: 0
vlan_tag_priority_val: 0
l3_filter_match: 0
l4_filter_match: 0
l3_l4_filter_no_match: 0
irq_pcs_ane_n: 0
irq_pcs_link_n: 0
irq_rgmii_n: 0
mtl_tx_status_fifo_full: 0
mtl_tx_fifo_not_empty: 0
mmtl_fifo_ctrl: 0
mtl_tx_fifo_read_ctrl_write: 0
mtl_tx_fifo_read_ctrl_wait: 0
mtl_tx_fifo_read_ctrl_read: 0
mtl_tx_fifo_read_ctrl_idle: 0
mac_tx_in_pause: 0
mac_tx_frame_ctrl_xfer: 0
mac_tx_frame_ctrl_idle: 0
mac_tx_frame_ctrl_wait: 0
mac_tx_frame_ctrl_pause: 0
mac_gmii_tx_proto_engine: 0
mtl_rx_fifo_fill_level_full: 0
mtl_rx_fifo_fill_above_thresh: 0
mtl_rx_fifo_fill_below_thresh: 0
mtl_rx_fifo_fill_level_empty: 0
mtl_rx_fifo_read_ctrl_flush: 0
mtl_rx_fifo_read_ctrl_read_data: 0
mtl_rx_fifo_read_ctrl_status: 0
mtl_rx_fifo_read_ctrl_idle: 0
mtl_rx_fifo_ctrl_active: 0
mac_rx_frame_ctrl_fifo: 0
mac_gmii_rx_proto_engine: 0
tx_tso_frames: 9225
tx_tso_nfrags: 11905
```

I ran the iperf test, 192.168.1.234 is a Windows machine running the iperf3 server.
```
root@Hachiroku:~# iperf3 -c 192.168.1.234 -p 5201
Connecting to host 192.168.1.234, port 5201
[ 5] local 192.168.1.199 port 40630 connected to 192.168.1.234 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 1.42 MBytes 11.9 Mbits/sec 10 58.5 KBytes
[ 5] 1.00-2.00 sec 1.10 MBytes 9.25 Mbits/sec 4 1.43 KBytes
[ 5] 2.00-3.00 sec 2.08 MBytes 17.5 Mbits/sec 6 58.5 KBytes
[ 5] 3.00-4.00 sec 941 KBytes 7.71 Mbits/sec 4 58.5 KBytes
[ 5] 4.00-5.00 sec 627 KBytes 5.14 Mbits/sec 6 58.5 KBytes
[ 5] 5.00-6.00 sec 1.76 MBytes 14.8 Mbits/sec 8 58.5 KBytes
[ 5] 6.00-7.00 sec 376 KBytes 3.08 Mbits/sec 4 1.43 KBytes
[ 5] 7.00-8.00 sec 68.4 KBytes 560 Kbits/sec 5 5.70 KBytes
[ 5] 8.00-9.00 sec 0.00 Bytes 0.00 bits/sec 5 8.55 KBytes
[ 5] 9.00-10.00 sec 55.6 KBytes 456 Kbits/sec 2 11.4 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 8.39 MBytes 7.04 Mbits/sec 54 sender
[ 5] 0.00-10.00 sec 8.25 MBytes 6.92 Mbits/sec receiver

iperf Done.
```

Here's a screenshot of the wireshark on my computer while SSHing.

Also, here's some good amount of outputs of the `tcpdump -i eth0 -n -v`
[tcpdump.txt](https://github.com/user-attachments/files/15990514/tcpdump.txt)

I also tested like this: BTT Pi2 -> My computer, which still gives me around 20% packet loss.

THANKFULLY, the USB ethernet dongle (Realtek 8153) works and is able to provide a somewhat decent experience with no packet loss.

I have no idea what happened to the onboard ethernet on both the PI2 and PI v1.2.