I have two HL7812 modules which I switched to USB comms to update FW ( AT+KUSBCOMP=1), one of the devices updated FW (HL7812.5.7.3.0) ok but after the update it became unresponsive over USB. The second device never connected to USB. The boot screen from UARTO states it is still configured for USB in out and error. Windows is stating “device descriptor request failed” I tried all the basic fixes for driver/pc issues and tried on multiple PCs with the same response. Is the anyway to “reset” device or override the USB command AT+KUSBCOMP=1? DO i have a two bricked devices? I have two more devices, but I am concerned about enabling USB. The same hardware has been used with the HL7810 without any issues. Here is the boot screen from a device which i have not activated USB on yet. HL7812.5.4.12.2-23.01.0.FreeRTOS.rc2 HL78xx.5.4.12.2.RK_03_02_00_22_24731_001.20230330 2023/03/30 08:42:08 IMEI-SV: 3511444414140612 Legato RTOS: 23.01.0.FreeRTOS.rc2 2023/03/30 05:53:54 atSwi: 23.01.0.FreeRTOS.rc2 UBOOT: 01.03 NP Package: RK_03_02_00_22_24731_001 Apps: RKAPP_03_02_00_22_24651_001__38231c6d829dbf9c71390d591eff7fc36cfd187b Using APP processor - no SB or 3B versions MAC Revision: REL_1250_03_02_22_REV_315256 MAC Package Version: ALT1250_03_02_00_22_24731_2G MAC Build Time: Dec_19_2022_14_20_32 PHY Revision: 12.50.314023 PHY Build Time: Nov_21_2022_00_15_42 PHY Build Info: releas_0 PMP Revision: 315260 PMP Version: 24721_PMP PMP build time: Sep_28_2022_14_51_22 DSP Revision: 63960 BB Product: 1250 BB HW Revision: 20 RFIC_6200 Revision: 00 NP Build Time: Mar 30 2023 08:40:18 NP Package Creation Time: 2023.03.30_08:42:08 C&V Ver: 9.68 Calibration date: 28.05.24 Calibrated NP package: RK_03_02_00_00_02 AISE Package : ISE2APP_00_00_00_09 AISE Build Time: Thu_05_19_2022_15_05

I don’t see such problem and I can use USB AT port to do AT communication afterwards: ati3 HL7812.5.7.3.0 OK at+kusbcomp? +KUSBCOMP: 0,0,0,0 OK at+switracemode? +SWITRACEMODE: RnD,9,2,0 OK AT+KUSBCOMP=1,1,2,3 OK at+cfun=1,1 OK I would suggest to enable RnD port in UART0 with AT+SWITRACEMODE command so that you can still enter AT command via UART0 port throughout your testing e.g. at!unlock="A710" OK at+switracemode? +SWITRACEMODE: RnD,9,2,0 OK at+switracemode=RnD OK at+switracemode? +SWITRACEMODE: RnD,9,2,0 OK

Thanks for the response, is there anything I can do with the two devices that are not able to communicate over USB at the moment? Is there a way to reset the devices or reprogram them over UART0 that eliminates the USB config?

Can you type anything in uart0? Can you communicate via usb in linux pc?

We can see a boot output on UART0 but haven’t been able to type anything, should we be able to type on UART0 if this is the config In: usbtty Out: usbtty Err: usbtty

I don’t have a linux setup at the moment, do you expect the USB to work differently on linux?

i don’t know as I don’t see any issue from above testing, you can give a trial and see if there is any luck I can also see other user can make it work in linux: [image] HL7812 USB Descriptors HL78 Yes, using a lot older version of Linux (on embedded device). HL7812 on Debian Wheezy.txt

WE had no luck with a linux system, Can you have any details about at+switracemode=RnD command I do not see this in the AT command reference? Any ideas how to reset the modem are there any options to “break” a FW update and cause a configuration reset?

[image] jrobinson2: but after the update it became unresponsive over USB. This happened to me one time. after a power cycle, it worked for me. [image] jrobinson2: We can see a boot output on UART0 but haven’t been able to type anything, should we be able to type on UART0 if this is the config also I did test this case as well. I dont remember what the issue was at that time but USB or UART1 were not working. so I reflashed the modem fw over UART0. Reconfigure HL78xx_download.ini for a update over uart

at!unlock=“A710” does not work for me and i get error when i send RnD command, any thoughts on this?

are we using the same firmware?

HL7812 USB failure

IoT Modules

jyijyi June 20, 2025, 2:16pm 13

How about this?

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HL7812 USB failure

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