Kyocera DIGNO Keitai 4

The Kyocera DIGNO Keitai 4 was released September 30th, 2022. It is the successor to the Kyocera DIGNO Keitai 3. The main differences in the newer model are a more powerful CPU, Android 10, the ability to root the device, and the lack of a flashlight.

The DIGNO 4 line is made up of the A202KC, A203KC, A204KC, KY-42C, and KY-43C. “A20XKC” will be used to collectively reference the A202KC, A203KC, and A204KC, and “KY-4XC” will be used for the KY-42C and KY-43C. Kyocera also makes the Kyocera Kids Keitai, a touchscreen smartphone that shares multiple specs with the DIGNO 4.

The A20XKC lineup is marketed by SoftBank and their subsidiary Y!mobile, and the KY-4XC lineup is marketed by NTT Docomo.

The OS on the DIGNO 4 uses much more of the internal storage, compared to the DIGNO 3. Both phones have 8 GB of built in storage, but the DIGNO 4 uses 4.4 GB, and the DIGNO 3 uses 2.7GB¹².

Only SD cards up to 32GB are only officially supported. However, users have successfully used SD cards as large as 400GB, indicating some microSDXC compatibility. SD cards can also be formatted as adoptable storage (internal storage) through unofficial means.

Despite having different model numbers, batteries across the DIGNO 4 lineup are interchangeable and have the same specs. The phones are also compatible with the battery model KYF36UAA, which comes from the KYF series of phones in recent models.

The DIGNO 3 battery is incompatible with the DIGNO 4¹³.

The A20XKC has an accelerometer, allowing for some apps to take advantage of auto rotation. However, it is not possible to enable auto rotation in the Android settings menu like the DIGNO 3 can.

Because Kyocera produces another flip-phone with the same SoC for the American market, the Kyocera DuraXV Extreme+, there may be additional software-locked radio bands on the DIGNO 4. However, there are various other inconsistencies with MediaTek's consumer-facing spec sheet for the Helio A22, such as a lack of 5GHz WiFi, WiFi 4 instead of 5, additional WiFi bands, and Bluetooth 5.1 instead of 5, potentially meaning the DIGNO 4 could have a different wireless setup. Docomo's DIGNO 4 offerings have different bands compared to SoftBank's, though, so at the very least, the missing bands on each carrier's phone could probably be unlocked. More research is needed. https://www.reddit.com/r/dumbphones/comments/1lph2qu/kyocera_rootgapps_help/nlsgnyi/

The DIGNO 4 has GPS built in, however due to the lack of Google Play Services most typical apps will either not provide a location or will not function. There also seems to be issues with the GPS working altogether, although the cause of this has yet to be determined.

See main article for details.

The phone does not support USB HID, meaning external devices, such as keyboards or mice, cannot be used via the USB port.

The USB port on the device exclusively uses “Audio Accessory Mode” for audio, which only allows audio as an analog signal¹⁸. This boils down to the device not supporting audio cables that have a DAC (Digital-to-Analog Converter) anywhere within them. Many USB-C to 3.5mm adapters have a DAC built into them, and will not function. Adapters of without DACs may be found online, but may not advertise this.

Inline remotes have yet to be tested.

Kyocera releases source code for the kernel and open source components of the operating system for all variants of the DIGNO 4.

Attempts to get custom ROMs, namely LineageOS, to run on the A202KC have been made. One person got as far as booting to TWRP, but could not proceed further as keyboard input would not work¹⁹. Keyboard input is reportedly not supported on the stock OS, either. More recently, a TWRP driver was made for devices without touch drivers, potentially enabling TWRP to be used on Android flip-phones²⁰.

Cellular carriers supply over-the-air updates to the DIGNO 4 in Japan. The A20XKC requires an active SoftBank SIM card to update, so it is not possible to receive updates outside of Japan. This cannot be mitigated using a Japanese VPN. Some KY-4XC users have received OTA updates in the US via T-Mobile²¹ and its MVNOs, including Mint Mobile²² and Tello Mobile²³. This may be because of the partnership between T-Mobile and Docomo, and the resulting configuration on T-Mobile's networks, but this has not been confirmed.

The A20XKC series oddly only has the open source code published up until 1.070XX, however phones with higher version numbers on those models have been confirmed. This list only contains confirmed versions we have seen so far.

Needs further documentation.

Due to the MediaTek chipset, these phones can be rooted using MTKClient. Rooting allows users to access system directories, run programs with superuser access, install GMS (LINK), and more. This capability has been verified on the A202KC, A203KC, A204KC, and KY-42C (up to version 1.090XX) variants, though there should not be any difference on the KY-43C.

The 1.090XX updates for the DIGNO 4 devices, released in mid 2025, patched the exploit in the preloader used by MTKClient to crash the DA. It may be possible to circumvent this by shorting test points inside the device. A method that does not require disassembly has been found. Please join one of our community servers for more information.

The DIGNO 4 does not come with a way to install third-party apps without external software. Android Debug Bridge (ADB) can be used with a computer to install additional apps.

Many third-party apps have partial navigability using the D-pad, but the cursor is often required to interact with some elements.

Due to the small screen size, some apps can not render properly. This can be mitigated by changing the display size.

This phone has a specific issue linked to third-party SMS apps where the apps have issues receiving texts. The behavior is such that when an alternative app is set as the default other than the stock “Mail” app or Google Messages, the phone will never receive texts while the app is not running²⁹. This seems to be directly linked to the specific CPU that the phone has, as a MediaTek process will delete the SMS in this scenario, citing that the app is not “whitelisted”³⁰. See the full article for details.

The A202KC is SoftBank's version of the DIGNO 4.

The A203KC is Y!Mobile's version of the DIGNO 4.

The A204KC is SoftBank Business' version of the DIGNO 4. It does not feature a camera.

The KY-42C is Docomo's variant of the DIGNO 4, though Docomo simply markets it as “DIGNO Keitai”, without the number at the end³¹. It has different cellular bands to the A20XKC lineup, as well as a different exterior design, and some minor software differences.

The KY-43C is Docomo's business variant of the DIGNO 4. Like the A204KC, it is missing a camera. The frequencies mirror those of the KY-42C, rather than any of the A20XKC variants. The KY-43C is the direct successor to the Kyocera DIGNO Keitai Basic.

The full model numbers for the A20XKC are formatted as: NPA20XKC.

NP and KC most likely stand for “New Product” and “KyoCera”, respectively³².

The DIGNO 4 has an official charging cradle. It is included with the A204KC, and is sold separately for the other models. The cradle does not support data transfer. It seems to be usable on the DIGNO 3, DIGNO 4, and Kyocera DIGNO Keitai Basic³³.

• Rooting the Kyocera DIGNO Keitai 4
• Improving performance on the Kyocera DIGNO Keitai 4
• Kyocera DIGNO Keitai 4 customization
• SD card limitations
• Third-party apps