Qin F21 Pro with Dumbdroid

最近入手了 Qin F21 Pro 這台按鍵式安卓手機。幾年前曾看過 Jose Briones 的評論影片，後來也陸續在 r/dumbphones 瀏覽過相關分享，但不曾對這支手機產生興趣。直到 2025 年 10 月，Dumbdroid 的開發者 Michal Brzozowski 發布了一篇文章，介紹這個作業系統的基礎資訊，才引起了我的關注。

什麼是 Dumbdroid？

Dumbdroid，中文或許可以譯為「笨卓」，是一款基於 LineageOS 的客製化作業系統。其底層採用了 Andy Yan 開發的 LineageOS 21.0 GSI，再由 Michal Brzozowski 針對特定機型進行客製化與優化。除了最初的 Qin F21 Pro 之外，目前亦擴大支援 Qin F22 Pro、Doov R77 Pro 與 R17 Pro 等按鍵式安卓手機(Keypad Android Phones)。Dumbdroid 作業系統吸引我的地方有以下三點：

1. Google 服務的選擇權：使用者可自由選擇是否安裝 Google Play Services 與 Google Play Store，無 Google 的版本則提供 microG 作為替代方案。
2. 頻繁的系統更新：官方持續釋出更新以修復錯誤並加入新功能。
3. 按鍵優化：針對 T9 鍵盤介面進行深度優化，營造出類似早期 Nokia 的互動體驗。

什麼是 Keypad Android Phones?

按鍵式安卓手機是指搭配實體按鍵鍵盤的 Android 智慧型手機，鍵盤的類型包含數字鍵盤(Numeric Keypad, 簡稱 T9)以及全鍵盤(QWERTY Keyboard），前者的代表如 CAT S22 Flip, Punkt MP02，後者如 Unihertz Titan, The Minimal Phone 等。

Dumbdroid 支援的四種機型，Qin 與 Doov 均為中國的品牌，這類手機的客群是以學生為主體，強調能減緩手機成癮問題，且支援家長進行遠端追蹤與監控。相對於一般智慧型手機，它們的售價較為親民。以 2022 年上市且仍在販售的 Qin F21 Pro 為例，入手價大約落在新台幣 3,000 至 4,000 元之間，具體取決於購買的版本與平台。

從 PUNKT MP02 到 QIN F21 PRO

我過去曾使用過 Punkt MP02，它也是運行客製化的 Android 作業系統（AphyOS）。這段經歷讓我深刻理解，廠商要將「觸控式」的系統底層調整為順暢的「按鍵式」人機交互模式，是多麼不容易的一件事；正是這樣的軟體開發瓶頸，導致 MP02 雖然擁有極佳的硬體設計，最終仍逐漸淡出市場。

我對於小手機有著莫名的喜好。或許是受到 MP02 的影響——那 100 克的輕巧重量、袖珍的外型與舒適的握感，讓我對其硬體設計讚不絕口。而 Qin F21 Pro 採用傳統的扁平長方體設計，重量也與 MP02 相差不遠，這便是我決定買一台來刷 Dumbdroid 作業系統的主要原因。

一波三折的刷機過程

在刷機過程中，我原本參考 Dumbdroid 的官方教學，但無論在 Windows 還是 Linux 環境下都無法成功。後來在 Discord Duoqin Hacking 頻道上，使用了網友 @zmwa 分享的可開機作業系統刷機包才順利完成。有興趣的朋友可以試試看這個方法，但務必記得事先做好資料備份。雖然 Dumbdroid 官網也有販售已經刷好系統的 R77 Pro，但近期在歐洲的需求量大增，因此自行購買機器來刷機，或許是目前比較快速的途徑。 

實際使用體驗

目前我已經使用將近兩週，整體的體驗可以拆成軟硬體兩個部分來分享：

• 軟體表現： Dumbdroid 作業系統運行相當穩定，我已經成功進行過兩次 OTA 系統更新。平時使用頻率不高，多數用來通話或接收 Signal 訊息，保守估計待機時間大約可達三天，這與我之前使用的 Pixel 8 表現相差不遠。不過，目前 Dumbdroid 尚不支援 Wi-Fi Calling 以及 Type-C 有線耳機，得觀望未來是否會釋出相關的修復更新。
• 硬體表現： F21 Pro 握持的手感略遜於 MP02，但優於 Light Phone 3。相機畫質雖然不佳，但已經足夠讓我快速掃描條碼以新增 Signal 設備——回想起幾年前在 MP02 上透過 Pigeon(第三方 Signal 客戶端)新增設備的折騰過程，現在的體驗已經讓我相當滿足。缺點方面，F21 Pro 的鈴聲偏小，且通話音質的清晰度也不及 MP02 與 Light Phone 3。

至於原本在使用的 Light Phone 3，由於其軟體功能仍在持續開發完善中，我或許會先將它收起來一陣子，等功能更齊全後再拿出來作為主力機使用。

參考資料

1. Install Dumbdroid yourself on a compatible device - Dumbdroid
2. Dumbdroid Releases - Github
3. Duoqin Hacking - Discord
4. Notes on Qin F21 Pro/AlikornSause

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Qin F21 Pro with Dumbdroid Review

I recently picked up a Qin F21 Pro keypad Android phone. A few years ago I had watched Jose Briones' review video, and later browsed related posts on r/dumbphones, but I never felt particularly drawn to this device — until October 2025, when Dumbdroid developer Michal Brzozowski published a post introducing the operating system's basics, and that's what finally caught my attention.

What is Dumbdroid?

Dumbdroid is a customized operating system based on LineageOS. Under the hood, it uses Andy Yan's LineageOS 21.0 GSI as its foundation, which Michal Brzozowski then customized and optimized for specific devices. Beyond the original Qin F21 Pro, it now also supports the Qin F22 Pro, Doov R77 Pro, and R17 Pro. The three things that drew me to Dumbdroid are:

• Choice over Google services: Users can freely choose whether to install Google Play Services and the Play Store; the Google-free version offers microG as an alternative.
• Frequent system updates: The developer continuously releases updates to fix bugs and add new features.
• Keypad optimization: Deeply optimized for T9 keypad input, delivering an experience reminiscent of early Nokia phones.

What are Keypad Android Phones?

Keypad Android Phones are Android smartphones equipped with a physical keyboard. The keyboard types include numeric keypads (T9) and full QWERTY keyboards. Notable examples of the former include the CAT S22 Flip and Punkt MP02, while the latter includes the Unihertz Titan and the Minimal Phone.

The four devices supported by Dumbdroid — Qin and Doov — are both Chinese brands. This category of phone is primarily marketed to students, with an emphasis on reducing phone addiction and supporting remote parental tracking and monitoring. They are also considerably more affordable than typical smartphones. The Qin F21 Pro, launched in 2022 and still available today, typically sells for around TWD 3,000 to 4,000 (roughly USD 90 to 125), depending on the version and platform.

From the Punkt MP02 to the Qin F21 Pro

I previously used the Punkt MP02, which also ran a customized Android OS (AphyOS). That experience gave me a deep appreciation for just how difficult it is to adapt a touchscreen-based system into a smooth keypad-driven interface — and it was precisely this software development bottleneck that caused the MP02, despite its excellent hardware design, to gradually fade from the market.

I have an inexplicable fondness for small phones, likely shaped by my time with the MP02 — its 100g weight, compact form factor, and comfortable grip left a strong impression on me. The Qin F21 Pro follows a traditional candybar design and weighs similarly, and that was the main reason I decided to pick one up and flash Dumbdroid onto it.

A Rocky Flashing Process

For the flashing process, I initially followed the official Dumbdroid instructions, but was unable to get it working on either Windows or Linux. I eventually succeeded using a bootable OS flashing package shared by Discord user @zmwa in the Duoqin Hacking channel. If you're interested, it's worth trying — just make sure to back up your data beforehand. While Dumbdroid's website does sell pre-flashed R77 Pro units, demand in Europe has surged recently, so buying a device and flashing it yourself may currently be the faster route.

Real-World Experience

After nearly two weeks of use, here are my impressions split into software and hardware:

Software: Dumbdroid runs remarkably stable — I've successfully completed two OTA system updates. I don't use the phone heavily; it's mostly for calls and receiving Signal messages, and I'd conservatively estimate about three days of standby time, roughly on par with my previous Pixel 8. That said, Dumbdroid currently does not support Wi-Fi Calling or wired Type-C headphones, and it remains to be seen whether fixes will arrive in future updates.

Hardware: The Qin F21 Pro's feel in hand is a notch below the MP02, but better than the Light Phone 3. The camera quality isn't great, but it's more than sufficient for quickly scanning a QR code to add a Signal device — a far smoother experience compared to the ordeal of adding a device through Pigeon (a third-party Signal client) on the MP02, so I'm quite satisfied. On the downside, the F21 Pro's ringtone volume is too low, and call clarity doesn't match either the MP02 or the Light Phone 3.

As for the Light Phone 3 I had been using, since its software features are still being actively developed, I'll probably set it aside for a while and bring it back as my daily driver once it's more fully featured.