nvtl_repair_imei.sh

#!/bin/sh

## This script was originally part of:
# https://hotspottoolkit.com/product/inseego-tool-download/
# It can be used to repair lost/broken IMEI on NVTL M2000B
# and similar on Inseego devices

echo "Content-type: text/plain"
echo ""

# Function to reverse a string
reverse_string() {
    echo "$1" | rev
}

# Function to convert IMEI to NV item content
imei_to_nv_item() {
    secret_setting="$1"

    if [ ${#secret_setting} -ne 15 ]; then
        echo "Error: IMEI string must be exactly 15 characters long."
        exit 1
    fi

    # Extract individual digit segments from the IMEI
    digit_1="${secret_setting:0:1}"        # First digit
    parity="${secret_setting:14:1}"        # Fifteenth digit (parity check digit)

    digit_2_3="${secret_setting:1:2}"      # Second and third digits
    digit_4_5="${secret_setting:3:2}"      # Fourth and fifth digits
    digit_6_7="${secret_setting:5:2}"      # Sixth and seventh digits
    digit_8_9="${secret_setting:7:2}"      # Eighth and ninth digits
    digit_10_11="${secret_setting:9:2}"    # Tenth and eleventh digits
    digit_12_13="${secret_setting:11:2}"   # Twelfth and thirteenth digits
    digit_14="${secret_setting:13:1}"      # Fourteenth digit

    # Combine segments into the final hex format
    hex_secret_setting="08${digit_1}${parity}$(reverse_string ${digit_2_3})$(reverse_string ${digit_4_5})$(reverse_string ${digit_6_7})$(reverse_string ${digit_8_9})$(reverse_string ${digit_10_11})$(reverse_string ${digit_12_13})${parity}${digit_14}"
    echo "$hex_secret_setting"
}

# Function to decode NV item content to IMEI
decode_nv_item_to_imei() {
    nv_content="$1"
    imei=""
    # Process the pairs, starting from the 4th character
    for i in $(seq 4 2 $((${#nv_content} - 3))); do
        pair="${nv_content:$i:2}"
        reversed_pair="${pair:1:1}${pair:0:1}"
        imei="$imei$reversed_pair"
    done
    # Add the last two characters as they are
    imei="$imei${nv_content: -2}"
    echo "$imei"
}

# Function to get the NV item content using modem2_cli
get_nv_item_content() {
    nv_item="nvm/num/550"
    modem2_cli efs_read <<EOF
$nv_item
1
EOF
}

# Function to write the NV item content using modem2_cli
write_nv_item_content() {
    nv_item="nvm/num/550"
    nv_content="$1"
    modem2_cli efs_write <<EOF
$nv_item
$nv_content
1
EOF
}

read -r post_data
# Extract IMEI from POST data
imei=$(echo "$post_data" | awk -F'=' '{print $2}')

if [ -z "$imei" ]; then
    echo "Error: IMEI value is missing."
    exit 1
fi

# Start IMEI to NV item conversion
new_nv_content=$(imei_to_nv_item "$imei")

# Log the NV content to be written
write_nv_item_content "$new_nv_content"

# Wait for a moment to ensure the write operation completes
sleep 2

# Verify the change
nv_content=$(get_nv_item_content | grep "Content:" | awk -F'[][]' '{print $2}')

# Decode the NV content and verify the IMEI
verified_imei=$(decode_nv_item_to_imei "$nv_content")
echo "Original IMEI: $imei"
#echo "Verified IMEI: $verified_imei"

# Check if the original IMEI matches the verified IMEI
if [ "$imei" = "$verified_imei" ]; then
    echo "IMEI verification successful."
else
    echo "IMEI verification failed. Original: $imei, Verified: $verified_imei"
f