Precautions

The following-mentioned flashing operation requires your familiarity with Linux and firmware flashing.
Please do not attempt to try it without sufficient experience!
Please do not attempt to try it without sufficient experience!
Please do not attempt to try it without sufficient experience!

as we will not be held responsible for any consequences. Thank you for your understanding.

There are risks involved in flashing the 4g ext, and it is necessary for you to have a certain understanding of these background information. During the testing process, it is also not possible for me to test whether all SIM cards worldwide can easily connect to the internet.

Purpose

To downgrade from 9011 to 9001.

Power On 4G ext

we assume that you already know how to power on the 4G ext by https://github.com/clockworkpi/uConsole/wiki/How-to-use-the-4G-extension

if not ,these steps are not safe for your device

Checking usb id

sudo lsusb

Bus 001 Device 009: ID 1e0e:9011 Qualcomm / Option SimTech, Incorporated

OR AT COMMAND

echo -en "AT+CUSBPIDSWITCH?\r\n" | sudo socat - /dev/ttyUSB2,crnl

we expecting response contains 9011, not 9001

Flashing part

if you got 9011 from

echo -en "AT+CUSBPIDSWITCH?\r\n" | sudo socat - /dev/ttyUSB2,crnl

then you can try to downgrade firmware

All processess done on uConsole CM4 or A06

Process Summary:

Download whole package from

https://github.com/clockworkpi/uConsole/raw/master/Bin/4G/LE20B06SIM7600G22_cpi_arm64.tar.gz

and uncompress it of course

tar zxvf LE20B06SIM7600G22_cpi_arm64.tar.gz
cd LE20B06SIM7600G22_cpi_arm64

First, send the command AT+BOOTLDR to /dev/ttyUSB3 to put the device into bootloader mode. At this point, the LED on the back will not light up.

echo -en  "AT+BOOTLDR\r\n" |sudo socat - /dev/ttyUSB3,crnl

Next, use sudo ./fastboot/bin/fastboot devices to ensure that the device is detected. It should display something like MDM9607 fastboot.
If there is no device information, the operation must be halted.

Then, use ./flash.sh from the compressed package to flash the firmware, which should take about 40 seconds.

here is the output of flash.sh

cpi@raspberrypi:~/LE20B04SIM7600G22_cpi $ ./flash.sh 
sending 'aboot' (447 KB)...
OKAY [  0.018s]
writing 'aboot'...
OKAY [  0.563s]
finished. total time: 0.583s
sending 'rpm' (156 KB)...
OKAY [  0.008s]
writing 'rpm'...
OKAY [  0.064s]
finished. total time: 0.072s
sending 'sbl' (210 KB)...
OKAY [  0.010s]
writing 'sbl'...
OKAY [  0.089s]
finished. total time: 0.099s
sending 'tz' (514 KB)...
OKAY [  0.020s]
writing 'tz'...
OKAY [  0.175s]
finished. total time: 0.195s
sending 'modem' (36096 KB)...
OKAY [  1.143s]
writing 'modem'...
OKAY [ 11.450s]
finished. total time: 12.593s
sending 'boot' (5536 KB)...
OKAY [  0.179s]
writing 'boot'...
OKAY [  1.744s]
finished. total time: 1.925s
sending 'system' (51072 KB)...
OKAY [  1.616s]
writing 'system'...
OKAY [ 17.308s]
finished. total time: 18.924s
sending 'recovery' (6010 KB)...
OKAY [  0.193s]
writing 'recovery'...
OKAY [  1.893s]
finished. total time: 2.086s
sending 'recoveryfs' (10240 KB)...
OKAY [  0.328s]
writing 'recoveryfs'...
OKAY [  3.229s]
finished. total time: 3.558s
rebooting...

finished. total time: 0.005s

Once the flashing is completed, the device will automatically reboot, and the LED on the back will light up again.

At this point, run sudo dmesg |tail to check for the following output:

[ 1033.836166] option 1-1.3:1.2: GSM modem (1-port) converter detected
[ 1033.836636] usb 1-1.3: GSM modem (1-port) converter now attached to ttyUSB0
[ 1033.837179] option 1-1.3:1.3: GSM modem (1-port) converter detected
[ 1033.837597] usb 1-1.3: GSM modem (1-port) converter now attached to ttyUSB1
[ 1033.838125] option 1-1.3:1.4: GSM modem (1-port) converter detected
[ 1033.838575] usb 1-1.3: GSM modem (1-port) converter now attached to ttyUSB2
[ 1033.839506] option 1-1.3:1.5: GSM modem (1-port) converter detected
[ 1033.840027] usb 1-1.3: GSM modem (1-port) converter now attached to ttyUSB3
[ 1033.840560] option 1-1.3:1.6: GSM modem (1-port) converter detected
[ 1033.840949] usb 1-1.3: GSM modem (1-port) converter now attached to ttyUSB4

If you see this output, it means that the firmware has been successfully flashed and the module is not bricked.

cpi@raspberrypi:~/LE20B06SIM7600G22_cpi_arm64 $ sudo lsusb
Bus 001 Device 008: ID 1e0e:9001 Qualcomm / Option SimTech, Incorporated

Useful AT commands

check firmware version

echo -en "AT+GMR\r\n" | sudo socat - /dev/ttyUSB2,crnl
+GMR: LE20B06SIM7600G22
OK

check sim card status

echo -en  "AT+cpin?\r\n" |sudo socat - /dev/ttyUSB2,crnl
+CPIN: READY
OK

check signal quality

echo -en  "AT+CSQ\r\n" |sudo socat - /dev/ttyUSB2,crnl
+CSQ: 20,99

OK

get imei

echo -en  "AT+CGSN\r\n" |sudo socat - /dev/ttyUSB2,crnl

86263605126xxxx

OK

echo -en  "AT+CIMI\r\n" |sudo socat - /dev/ttyUSB2,crnl
46001341620xxxx

OK