--- title: #4: U-Boot menu on Flipper One screen slug: one/dev-log/4 docTags: createdAt: 2026-06-29T13:34:26.711Z --- This is our Dev Log where we share how the development of Flipper One is going. **In this Dev Log:** U-Boot menu, ongoing Wi-Fi testing, Flipper One UI in a browser, and an updated fan shield module. *** ## U-Boot menu runs on Flipper One screen The U-Boot menu now works directly on Flipper One, without the need to plug an external display. You can choose different kernels and systemd targets before the Linux kernel boots. ::embed[]{url="https://www.youtube.com/watch?v=oI6Vl_uoAwI"} Our [patched U-Boot](https://github.com/flipperdevices/u-boot) is based on a slightly modified U-Boot with LCD and button drivers. In the release version of Flipper OS, the boot menu will likely be drawn by a small program compiled into `initramfs` and executed after the kernel starts. The cold boot time (from the CPU power-on to a working menu) still has room for improvement: ```console $ tio --timestamp --timestamp-format 24hour-delta -b 1500000 /dev/tty.usbmodemflip_one_debug2 ... [00:00:02.788] I/TC: OP-TEE version: 51d99cd (gcc version 14.2.0 (Debian 14.2.0-19)) #1 Wed Jun 24 10:30:06 UTC 2026 aarch64 ... ``` See the [full boot log](https://pastebin.com/raw/A0RUrdRm). *** ## Multiple tests of the Wi-Fi chipset We chose the MediaTek MT7921AU Wi-Fi chipset for Flipper One. On paper, it operates on 2.4/5/6 GHz bands, can be a station and an access point, supports monitor mode and packet injection, and has an open-source driver in the mainline Linux kernel. It looked like a great hacker-friendly chipset, but then the actual tests came in. ![MT7921AU Wi-Fi chip on the Flipper One board](https://api.archbee.com/api/optimize/3StCFqarJkJQZV-7N79yY/cjYtUCTsG2GhwwdEBNIJK_wifi-chip-mt7921au.jpg) We tested the chip and got the following results: - ✅ *Station mode (STA)*. - ✅ *Access Point mode (AP)*. - ✅ *AP+STA Single-Channel Concurrency (SCC)* [(see report)](docId\:fc3x8EkoySgRIbTltZM6x). - ✅ *Monitor mode* [(see report)](docId\:LyWkeJKS03rrpu1QXXUU6). - *Dual-band dual-concurrent (DBDC)*: - ❌ *Dual-band AP+STA* [(see report)](docId\:NYmiebjtkulD77IesJlHs). - ✅ *Dual-band AP+STA with a driver patch*. Our contributor *@germiBest* made tests with a simple driver patch and proved that dual-band AP+STA can be fixed [(see report)](https://github.com/flipperdevices/flipperone-docs/pull/387). - ❌ *Dual-band AP+AP* [(see report)](docId\:NYmiebjtkulD77IesJlHs). This combination wasn't expected to work, and we made a report to prove that. - Operating on ✅ 2.4 / ✅ 5 / ❌ 6 GHz. Even configured for a region with 6 GHz enabled, the chip didn't allow us to use this band. Last week, [we asked for your help with Wi-Fi testing](https://x.com/Flipper_RND/status/2069083164190929111) — thanks for your research and ideas. We've also contacted MediaTek about the issue with dual-band AP+STA, but got no response so far. Besides, there are [several driver patches](https://lore.kernel.org/linux-wireless/?q=build+iface+combinations+dynamically) coming to the upstream — although, we can't guarantee they will succeed soon. Wrapping it all up, we can expect that dual-band AP+STA will be enabled, but dual-band AP+AP won't ever work on this chip. :::hint{type="info"} So, with all the confirmed and expected results, do you think it's a good choice of Wi-Fi chip? Will it still do the job for you? Please share what you think in the comments below. ::: *** ## Flipper One Lab for UI testing — the 1st community project *@kalicyh* built the [Flipper One Lab](https://github.com/kalicyh/flipperone-lab) — a container-based emulator of Flipper One's FlipCTL UI right in a web browser, no physical device needed. Check out this demo (and note that it's a browser tab!): ::embed[]{url="https://www.youtube.com/watch?v=6HPHjbBp00M"} This is a great example of a Flipper One [community project](docId\:Xqaz9ZzclnBl0Awu3zH6q). If you work on something similar, let us know in the comments below! ## Fan shield — the 1st module contribution Remember the fan shield from Developer Log #1? We gave some feedback and *@yupych* [improved the model](https://github.com/flipperdevices/flipperone-mechanics/pull/31). ![Updated fan shield module render](https://api.archbee.com/api/optimize/3StCFqarJkJQZV-7N79yY/zU1aeWEQezgRGHSMFwVz4_fan-shield-improved.png) Watch our industrial designer *@r-galeev* test the fan shield with a Flipper One prototype: ::embed[]{url="https://www.youtube.com/watch?v=ZmNi7M4flao"} You're welcome to propose your own Flipper One modules. Check out the [contribution guide](docId:0DDVbIoaWJaz2P653X569) and open a pull request in [flipperdevices/flipperone-mechanics](https://github.com/flipperdevices/flipperone-mechanics). *** ## Join Flipper One development and make your contribution - We're still looking for a FlipCTL architecture lead. Read the [blog post about FlipCTL](https://blog.flipper.net/flipctl-our-gui-framework-for-embedded-linux-systems/) and propose your vision of its architecture. - Building a project that helps test and improve Flipper One? Please tell us about it in the comments or add it on the [community projects](docId\:Xqaz9ZzclnBl0Awu3zH6q) page. - 3rd-party module contributions are welcome! Check out the [contribution guide](docId:0DDVbIoaWJaz2P653X569) and open a pull request in [flipperdevices/flipperone-mechanics](https://github.com/flipperdevices/flipperone-mechanics). - We have many other tasks open to the community! See the full list on the [🚧 Open tasks](https://docs.flipper.net/one/open-tasks) page. See you in the next Dev Log!