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 i…

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 co…

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 De…

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 c…

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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