# USB Serial Driver Request **URL:** \ **Category:** KVM\ **Created:** [September 28, 2026, 8:54am UTC](https://forum.gl-inet.com/t/usb-serial-driver-request/71641 "2026-09-28T08:54:12Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![yaxi](https://forum-assets.gl-inet.com/letter_avatar_proxy/v4/letter/y/50afbb/32.png) [@yaxi](https://forum.gl-inet.com/u/yaxi)\ **Post date:** [September 28, 2026, 8:54am UTC](https://forum.gl-inet.com/t/usb-serial-driver-request/71641/1 "2026-09-28T08:54:12Z")
Hi, can GL-iNet provide the driver (i think i’ll need both `serial.ko` and `pl2303.ko`) for my USB serial? I vaguely recall earlier version had it supported, but it doesn’t seem like the case anymore. ```auto T: Bus=02 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 3 Spd=12 MxCh= 0 D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1 P: Vendor=067b ProdID=23a3 Rev= 3.05 S: Manufacturer=Prolific Technology Inc. S: Product=USB-Serial Controller S: SerialNumber=ECASb153609 C:* #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=100mA I:* If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=(none) E: Ad=81(I) Atr=03(Int.) MxPS= 10 Ivl=1ms E: Ad=02(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms E: Ad=83(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms bash-4.4# uname -a Linux glkvm 4.19.111 #1 SMP PREEMPT Wed Sep 16 15:47:42 CST 2026 armv7l GNU/Linux bash-4.4# cat /proc/version Linux version 4.19.111 (tinghai@gl-MS-7D70) (gcc version 6.3.1 20170404 (Linaro GCC 6.3-2017.05)) #1 SMP PREEMPT Wed Sep 16 15:47:42 CST 2026 ``` ---
**Author:** ![Thalia](https://forum-assets.gl-inet.com/letter_avatar_proxy/v4/letter/t/9de053/32.png) [@Thalia](https://forum.gl-inet.com/u/Thalia)\ **Post date:** [September 28, 2026, 10:44am UTC](https://forum.gl-inet.com/t/usb-serial-driver-request/71641/3 "2026-09-28T10:44:20Z")
Hi, please let us know which firmware version and KVM model you're using. ---
**Author:** ![yaxi](https://forum-assets.gl-inet.com/letter_avatar_proxy/v4/letter/y/50afbb/32.png) [@yaxi](https://forum.gl-inet.com/u/yaxi)\ **Post date:** [September 28, 2026, 5:57pm UTC](https://forum.gl-inet.com/t/usb-serial-driver-request/71641/4 "2026-09-28T17:57:28Z")
```auto # cat /etc/version RK_MODEL=RM1 RK_VERSION=V1.10.1 release3 RK_OTA_HOST= ``` ---
**Author:** ![Thalia](https://forum-assets.gl-inet.com/letter_avatar_proxy/v4/letter/t/9de053/32.png) [@Thalia](https://forum.gl-inet.com/u/Thalia)\ **Post date:** [September 29, 2026, 2:20am UTC](https://forum.gl-inet.com/t/usb-serial-driver-request/71641/5 "2026-09-29T02:20:01Z")
Hi, PL2303 is supported. The PL2303 driver is built into the kernel. If you have any issues using it, please provide us with the kernel log: ```auto dmesg | tail -n 200 ``` ---
**Author:** ![yaxi](https://forum-assets.gl-inet.com/letter_avatar_proxy/v4/letter/y/50afbb/32.png) [@yaxi](https://forum.gl-inet.com/u/yaxi)\ **Post date:** [September 29, 2026, 5:27am UTC](https://forum.gl-inet.com/t/usb-serial-driver-request/71641/6 "2026-09-29T05:27:24Z")
You're right, it's built in to kernel. My initial post body has `/sys/kernel/debug/usb/devices` output showing the device isn't bind to any driver. After some digging, it looks like my device is a refresh'ed PL2303 adapter, such that its driver is only added after kernel 5.5 with more than just VID:PID table change. so the KVM's kernel predates that. I attempted manually binding the driver; while that creates the device `ttyUSB0`, it doesn't work. ```auto [root@glkvm:/sys/bus/usb-serial/drivers/pl2303]# echo 067b 23a3 > new_id [root@glkvm:/sys/bus/usb-serial/drivers/pl2303]# dmesg | tail -30 [167972.962166] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [167972.962187] usb 2-1: Product: USB-Serial Controller [167972.962206] usb 2-1: Manufacturer: Prolific Technology Inc. [167972.962225] usb 2-1: SerialNumber: ECASb153609 [168253.080371] pl2303 2-1:1.0: pl2303 converter detected [168253.081032] pl2303 2-1:1.0: pl2303_vendor_read - failed to read [8484]: -32 [168253.083684] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0404]: -32 [168253.085045] pl2303 2-1:1.0: pl2303_vendor_read - failed to read [8484]: -32 [168253.087024] pl2303 2-1:1.0: pl2303_vendor_read - failed to read [8383]: -32 [168253.089058] pl2303 2-1:1.0: pl2303_vendor_read - failed to read [8484]: -32 [168253.091107] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0404]: -32 [168253.093204] pl2303 2-1:1.0: pl2303_vendor_read - failed to read [8484]: -32 [168253.095115] pl2303 2-1:1.0: pl2303_vendor_read - failed to read [8383]: -32 [168253.097082] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0000]: -32 [168253.099719] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0001]: -32 [168253.100998] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0002]: -32 [168253.101703] usb 2-1: pl2303 converter now attached to ttyUSB0 [168299.777113] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0008]: -32 [168299.778982] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0009]: -32 [168299.785100] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0000]: -32 [168299.793018] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0000]: -32 [168299.799059] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0000]: -32 [168317.738581] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0000]: -32 [168330.913879] RKMODULE_GET_HDR_CFG [168330.914003] rkisp rkisp-vir0: can not get first iq setting in stream on [168330.915151] rockchip-mipi-dphy-rx ff4b0000.csi-dphy: stream on:1 [168330.915186] rockchip-mipi-dphy-rx: data_rate_mbps 1000 [168330.916246] rkisp0: MIPI error: packet: 0x01000000 [168330.927355] rkisp0: MIPI error: packet: 0x00000101 [168458.725046] pl2303 2-1:1.0: pl2303_vendor_write - failed to write [0000]: -32 ``` Looks like the i'd have to either use a different adapter, or to build the backported driver. Can you point me to where to find the kernel source and toolchain, so i can build driver for that? Or does GL-iNet has a way to ask if chip vendor (rockchip) already has a backported driver? ---
**Author:** ![wna](https://forum-assets.gl-inet.com/letter_avatar_proxy/v4/letter/w/8e8cbc/32.png) [@wna](https://forum.gl-inet.com/u/wna)\ **Post date:** [September 29, 2026, 7:51am UTC](https://forum.gl-inet.com/t/usb-serial-driver-request/71641/7 "2026-09-29T07:51:18Z")
We recommend trying another adapter. The kernel version of RM1 is 4.19. Below are the corresponding source code and toolchain: [https://github.com/gl-inet/kernel-4.19](https://github.com/gl-inet/kernel-4.19) [https://github.com/gl-inet/glkvm-opensdk-rv1126](https://github.com/gl-inet/glkvm-opensdk-rv1126) Other devices such as RM1V2 run kernel version 6.1. ---
**Author:** ![yaxi](https://forum-assets.gl-inet.com/letter_avatar_proxy/v4/letter/y/50afbb/32.png) [@yaxi](https://forum.gl-inet.com/u/yaxi)\ **Post date:** [September 30, 2026, 5:54am UTC](https://forum.gl-inet.com/t/usb-serial-driver-request/71641/8 "2026-09-30T05:54:55Z")
Thanks! gpt-6.1-sol built me the back ported driver very quickly from those kernel source and toolchain. Putting the driver here since it might be helpful to others. [pl2303\_rm1.ko.zip](https://forum.gl-inet.com/uploads/short-url/3kUaJr5DbEKGURc2h8BMydIrWMj.zip) (92.7 KB) Expect logs like those: ```auto [179.255076] usb 2-1: new full-speed USB device number 3 using ohci-platform [179.487159] usb 2-1: New USB device found, idVendor=067b, idProduct=23a3, bcdDevice= 3.05 [179.487208] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [179.487224] usb 2-1: Product: USB-Serial Controller [179.487238] usb 2-1: Manufacturer: Prolific Technology Inc. [179.487251] usb 2-1: SerialNumber: ECASb153609 [179.490344] pl2303_rm1 2-1:1.0: pl2303_rm1 converter detected [179.491383] usb 2-1: pl2303_rm1 converter now attached to ttyUSB0 ```