Howdy! I had posted here at a b c;still waiting , in the end I solved with a lot of reading and countless tests. I was able to do this because a possible modem corruption would not have resulted in significant economic damage.The usb_boot method undocumented using test pins was not successful:“USB_BOOT” to 1.8 V before “VDD_EXT” is powered on connect the two pins before power on module, then after the QDloader port appeared, please disconnect”, in fact, it brought the modem into an unstable situation in edl_mode with bootloops! I tried to use also QPST with the fw of quectel without success, finally out of desperation inspired by phone_modder: “EDL is implemented by the SoC ROM code (also called PBL)” I used a fw for x55 of other brand complete with files .elf .img and prog_nand_firehose_filename_bootloader_ENPRG9x07.mbn, result that the first part of the flash worked but brought the modem from edl/Qdl into 900e.Positive note that the modem had a stable port however not edl.The Qualcomm x55 (snapdragon) has the ability to restore both in adb_fastboot and with firehose but you need to block the bootloader:“Bridge Power supply for RFFE (PO) Power Output to Ground GND disabling RF Front-End Control Interface get QDL_mode” So I took a cue from the documentation of the Development Kit board:“Turn On EDL Switch in the Development Kit to ON/EDL USB BOOT once flashed Turn OFF EDL Switch and Restart Device” and I thought that doing something similar on the modem could work by allowing risk.Then reading the doc_hardware I noticed pin 65 (Note that strangely no longer documented in the next series) I adhered to a very thin copper wire on rubberized paper and adhered to the top half of the pin_slot and up to rest of the other end on the plate that acts as ground.With great wonder device manager shows the door 900e turn into “other_brand” QDLoader 9008…there was to imagine it having flashed another fw.However I did not hesitate, leaving the bridge active ie the pin 65 put on the ground as specified here modding502|690x350
.I used the first Qflash with the specific quectel fw and wonderfully …success! I removed the wire and the card is resurrected.Installed the drivers I found the modem working but although unlocking the QADBKEY the modem was in FTM mode.In the files of the folder quectel_fw_package there are no .Xqcn and qdl files so given the results on the forum I “made use” of the files of the other brand; I used the Qpstconfig procedure and loaded the file grazie_molte.xqcn of 3.030kb.What about the command AT+CFUN? was no longer 5 and the AT+QRFTEST=“mode” no longer 1 but ZERO! Concluding, I suspect that the board (not in my hands) had a shock on the antennas side, so much so that two of the Mhf4 plugs were literally disconnected on the first attempt to connect the Rf part.Anyway the RM502Q-GL works with the antenna on the semi-destroyed port 0 ;when I have time will rebuild even the damaged plugs.
Your post is too long.
Is the problem now that you can’t connect to the Internet?
AT+CFUN? What will be returned?
Hi Bean, the modem work, but I need if there is a fresh firmware and the XQCN file.
Thanks
Is the IMEI
355878110128188 ?
IMEI： 355878110128188 yes
I have checked internally that there is no xqcn file backup file for each Quectel modem.
There is this version RM502QGLAAR11A02M4G_01.200.01.200, I can send it to you.
However, please note that after flashed this version, you cannot roll back the version.
Do not try the RM502QGLAAR11A02M4G_01.001.01.001 and any other any more.
Thanks, I know that this is a signed version, hope is not eFuse.For my non official xqcn file flashed , will work whith the new version?
XQCN is not efuse.
But for each Quectel modem, the Quectel would adjust the RF parameters. Each Quectel modem has different parameter.
If you flash the modem with a common xqcn file, the performance might not be as good.
If you flashed with xqcn file from another Quectel modem but not RM502QGLAA, the modem might not work.
So it is not reconmended and not allowed to modify the xqcn file.
Please check the message. And please kindly read the release note.
For the non official xqcn you mentioned, please just try it only on that one modem.
Do not try to flash it into any Quectel modem!
Thanks! All good & works, although i had to flash with Q_4.18.
[2024-03-07 10:37:38:673_R:] RM502QGLAAR11A02M4G_01.200.01.200
nice end for a few $ modem_card!
Hello dear @Bean.Wang-Q ,
Regarding the downgrade of the modem, I understand that you said you can’t rolling back to earlier firmware versions. However I did this thing few times back and forth, before I knew this information. What are the consequences of downgrading from AR13A03 to AR11A02?
For this example
R11 is the version from Qualcomm.
A02 is the version defined by Quectel.
R11 and R13 is not the same Qualcomm version. Normally it is not allowed to upgrade not matter from R11 to R13 or even R13 to R11.
In some cases, it is allowed to upgrade from R11 to R13, but you need the confirmation from the Quectel. Normally, it is not allowed to downgrade from R13 to R11.
A02 is the firmware version of Quectel so in most cases it is allowed to upgrade from A02 to A03 and there is of no problem to downgrade from A03 to A02.
But
_01.200.01.200 is also very important version.
200 means that even the A03 could not downgrade to A02. There’s a special meaning. Please check the Quectel Release note in the zip of the firmware.
Thank you so much for the comprehensive response. I am currently running firmware version RM502QAEAAR13A04M4G and my modem seems fine despite the improper downgrade/upgrade. Just in case is there a command to reset the modem to factory defaults? Thank you!
There is no such AT command to set the modem to download mode.
There is no command to restore factory Settings. EC25 has such a command, but it needs to be backed up in advance.