0bda:815a Realtek USB 10G LAN, carrier constantly on and off

I got one of these during my trip to Shenzhen at half price than aliexpress.

USB 10G LAN. comments said there could be chips from intel 520/540 or realtek.

idVendor 0x0bda Realtek Semiconductor Corp. idProduct 0x815a USB 10/100/1G/2.5G/5G/10G LAN

I plugged in pve 9.1.2 (current on 07 Dez 2025).

Didn't work as is.

tried this gist with current driver from realtek 2.21.4 and linux bond with this guide.

# ethtool -i enx1c860b39570d
driver: r8152
version: v2.21.4 (2025/10/28)
firmware-version: 
expansion-rom-version: 
bus-info: usb-0000:04:00.3-2
supports-statistics: yes
supports-test: no
supports-eeprom-access: no
supports-register-dump: no
supports-priv-flags: no

from this post I should get a firmware-verion, but nada

# lsusb
Bus 004 Device 004: ID 0bda:815a Realtek Semiconductor Corp. USB 10/100/1G/2.5G/5G/10G LAN

# lsusb -v -s 004:004
Bus 004 Device 004: ID 0bda:815a Realtek Semiconductor Corp. USB 10/100/1G/2.5G/5G/10G LAN
Negotiated speed: SuperSpeed+ (10Gbps)
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               3.20
  bDeviceClass            0 [unknown]
  bDeviceSubClass         0 [unknown]
  bDeviceProtocol         0 
  bMaxPacketSize0         9
  idVendor           0x0bda Realtek Semiconductor Corp.
  idProduct          0x815a USB 10/100/1G/2.5G/5G/10G LAN
  bcdDevice           30.00
  iManufacturer           1 Realtek
  iProduct                2 USB 10/100/1G/2.5G/5G/10G LAN
  iSerial                 7 00031C860B39570D
  bNumConfigurations      3
.....

but as soon I connect to rj45 cable, it just repeats carrier on and off, how do I debug from here?

# dmesg | grep -i enx1c860b39570d
[    2.852015] r8152 4-2:1.0 enx1c860b39570d: renamed from eth0
[   11.011821] r8152 4-2:1.0 enx1c860b39570d: renamed from eth0
[   18.300871] bond0: (slave enx1c860b39570d): Enslaving as a backup interface with a down link
[   18.310481] r8152 4-2:1.0 enx1c860b39570d: entered allmulticast mode
[   18.310686] r8152 4-2:1.0 enx1c860b39570d: entered promiscuous mode
[  186.401403] r8152 4-2:1.0 enx1c860b39570d: Promiscuous mode enabled
[  186.401526] r8152 4-2:1.0 enx1c860b39570d: carrier on
[  186.484889] bond0: (slave enx1c860b39570d): link status definitely up, 1000 Mbps full duplex
[  187.431258] r8152 4-2:1.0 enx1c860b39570d: carrier off
[  187.432686] bond0: (slave enx1c860b39570d): speed changed to 0 on port 2
[  187.521739] bond0: (slave enx1c860b39570d): link status definitely down, disabling slave
[  189.729305] r8152 4-2:1.0 enx1c860b39570d: Promiscuous mode enabled
[  189.729451] r8152 4-2:1.0 enx1c860b39570d: carrier on
[  189.812314] bond0: (slave enx1c860b39570d): link status definitely up, 1000 Mbps full duplex
[  190.759208] r8152 4-2:1.0 enx1c860b39570d: carrier off
[  190.761024] bond0: (slave enx1c860b39570d): speed changed to 0 on port 2
[  190.849711] bond0: (slave enx1c860b39570d): link status definitely down, disabling slave
[  193.313546] r8152 4-2:1.0 enx1c860b39570d: Promiscuous mode enabled