diff --git a/docs/OpenMobileNetworkToolkit.md b/docs/OpenMobileNetworkToolkit.md
index 929ba881..c9036893 100644
--- a/docs/OpenMobileNetworkToolkit.md
+++ b/docs/OpenMobileNetworkToolkit.md
@@ -15,6 +15,8 @@
     * [Slicing](./slicing.md)
     * [InfluxDB](./influxdb.md)
     * [Workprofile](./workprofile.md)
+    * IMS
+        * [How-to Enable IMS on 999xx PLMNs](./howto_ims.md)
     * [Settings](settings/settings.md)
         * [Logging](settings/logging.md)
         * [Mobile Network](settings/mobile_network.md)
diff --git a/docs/carrier-permissions.md b/docs/carrier-permissions.md
index 0e149f9c..ac782822 100644
--- a/docs/carrier-permissions.md
+++ b/docs/carrier-permissions.md
@@ -32,4 +32,30 @@ aram_store_ref_ar_do --aid ffffffffffff --device-app-id E849B63A7B96E571F788FC58
 ```
 This assumes the credentials to access the card are stored in the pySim format.
 
+---
+
+#### Alternative Solution
+
+The `aram_store_ref_ar_do` command may return the following error:
+```
+EXCEPTION of type 'ValueError' occurred with message: Dict [{'ref_ar_do': [{'ref_do': [{'aid_ref_do': 'FFFFFFFFFFFF'}, {'dev_app_id_ref_do': 'E46872F28B350B7E1F140DE535C2A8D5804F0BE3'}]}, {'ar_do': [{'apdu_ar_do': {'generic_access_rule': 'always'}}, {'perm_ar_do': {'permissions': '0000000000000001'}}]}]}] doesn't contain expected key command_store_ref_ar_do
+```
+
+In this case, the GP provided by the [CoIMS_Wiki](https://github.com/herlesupreeth/CoIMS_Wiki) project can be used as an alternative solution by following the steps below. To implement this solution, the KIC1, KID1 and KIK1 keys of the SIM card are required.
+```bash
+git clone https://github.com/herlesupreeth/CoIMS_Wiki
+cd CoIMS_Wiki
+alias gp="java -jar $PWD/gp.jar"
+gp --key-enc <KIC1> --key-mac <KID1> --key-dek <KIK1> -lvi
+# Unlock the SIM card for easier installation of applet
+gp --key-enc <KIC1> --key-mac <KID1> --key-dek <KIK1> --unlock
+# Install ARA-M Java Card applets on USIM/ISIM
+gp --install applet.cap
+# Push the SHA-1 certificate of the OMNT app onto ARA-M in USIM/ISIM
+gp -a 00A4040009A00000015141434C0000 -a 80E2900033F031E22FE11E4F06FFFFFFFFFFFFC114E849B63A7B96E571F788FC5845C4AA3C520D18E8E30DD00101DB080000000000000001
+# Check the list of installed certificates
+gp --acr-list-aram
+```
+
+
 [Home](OpenMobileNetworkToolkit.md)
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diff --git a/docs/howto_ims.md b/docs/howto_ims.md
new file mode 100644
index 00000000..5732d14e
--- /dev/null
+++ b/docs/howto_ims.md
@@ -0,0 +1,26 @@
+# How-to Enable IMS on 999xx PLMNs
+
+It is possible to activate IMS on PLMN IDs such as 999xx using OMNT. To achieve this, the following steps should be followed:
+
+1. In addition to the **internet** APN, create another APN value for IMS on the smartphone.
+
+* Go to `Settings/Network and Internet/SIMs/<Name of SIM card>`
+* Add the APN in `Access point names`. (Name: *ims*, APN: *ims*, APN type: *ims*, APN protocol: *IPv4*, APN roaming protocol: *IPv4*). After that, save it and leave the **internet** APN selected.
+
+2. Disable SQN checking on SIM cards. (See the *Disabling / Enabling SQN validation* section of the sysmoISIM user manuals)
+```bash
+# Add '--pcsc-shared' flag if the card status includes 'Shared Mode'
+# p: Card reader number in the 'pcsc_scan' output
+./pySim-shell.py --pcsc-shared -p 1
+pySIM-shell > verify_adm <your-admin-key>
+pySIM-shell > select ADF.USIM/EF.USIM_SQN
+pySIM-shell > read_binary_decoded # Check the "sqn_check" value
+pySIM-shell > update_binary_decoded --json-path $.flag1.sqn_check false
+pySIM-shell > read_binary_decoded # Check again if the "sqn_check" value is false
+```
+
+3. IMS activation by overriding the IMS settings may be required if the PLMN ID of the SIM card is not in the [carrier list](https://android.googlesource.com/platform/packages/providers/TelephonyProvider/+/refs/heads/main/assets/sdk34_carrier_id/carrier_list.textpb). SysmoISIM cards can connect to IMS without needing extra SIM card configuration if the PLMN ID is **00101**, but for some PLMN IDs such as **999xx**, the following steps should be applied:
+
+* The carrier permissions should be activated. (See [SIM Card Setup for Carrier Permissions](./carrier-permissions.md))
+
+* Open the OMNT app and enable `CARRIER_VOLTE_AVAILABLE_BOOL` and `CARRIER_VOLTE_PROVISIONED_BOOL` in `Settings/Mobile Network/Android 10 API 29 (Q)`. Then, press `Apply carrier settings now`.
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