Quansheng UV-K5/K6 Custom Firmware (takyonxxx Edition)

Forked from egzumer/uv-k5-firmware-custom, which is a merge of OneOfEleven custom firmware with fagci spectrum analyzer. All based on DualTachyon's open firmware.

Warning: Use this firmware at your own risk (entirely). There is absolutely no guarantee that it will work in any way shape or form on your radio(s), it may even brick your radio(s), in which case, you'd need to buy another radio. Anyway, have fun.

takyonxxx Custom Changes

Simplified Menu System

The menu has been reorganized into visible and hidden sections. Frequently used items are immediately accessible, rarely used items are moved to the hidden menu (accessible by holding PTT + upper side button during power-on).

Visible menu (13 items): Sql, Step, TxPwr, W/N, Demod, Mic, AM Fix, VOX, BatVol, BackLt, Beep, RxMode, VER

Hidden menu (moved from visible): RxDCS, RxCTCS, TxDCS, TxCTCS, TxODir, TxOffs, BusyCL, Compnd, ChSave, ChDele, ChName, Scramb, ScAdd1/2, SList/1/2, ScnRev, F1Shrt/Long, F2Shrt/Long, M Long, KeyLck, TxTOut, BatSav, MicBar, ChDisp, POnMsg, BatTxt, BLMin/Max, BltTRX, Roger, STE, RP STE, 1 Call, all DTMF items, plus the original hidden items (F Lock, Tx 200/350/500, 350 En, ScraEn, FrCali, BatCal, BatTyp, Reset).

Accessing the hidden menu: Turn off the radio. Press and hold both the PTT button and the upper side button simultaneously, then turn the radio on while keeping both buttons held. Release after the radio boots. The menu will now show all items including the hidden ones.

Automatic Demodulation by Frequency

The radio automatically selects the correct demodulation mode based on frequency:

This works in three places: when entering a frequency via keypad, when tuning with UP/DOWN in VFO mode, and when loading channels from EEPROM. The mode can still be changed manually via the Demod menu item.

TX on All Frequencies

The TX_freq_check function has been modified to allow transmission on all valid frequencies (BX4819 chip gap excluded). The ENABLE_TX_WHEN_AM flag is enabled, allowing TX in AM mode. Note that BK4819 hardware only supports FM modulation for TX regardless of the demod setting.

Spectrum Analyzer

The original fagci spectrum analyzer is retained with peak hold functionality. Access via the assigned side button.

Recommended Airband Frequencies (Ankara)

For testing AM reception on the aviation band (118-136 MHz, auto-AM enabled):

• 118.100 — Esenboğa TWR (Tower)
• 119.100 — Esenboğa Approach
• 121.500 — International emergency frequency
• 121.800 — Esenboğa Ground
• 124.000 — Ankara ATIS (continuous automated broadcast, best for testing)
• 127.800 — Ankara ACC (Area Control)

Version String Fix

The version string in the menu has been split across two lines so it fits the 128px wide display without truncation.

Demodulation Menu Renamed

The demodulation type menu item has been renamed from "Demodu" to "Demod" for clarity.

FM/AM Demodulation Improvements

Two fixes to improve AM reception quality:

AGC bit bug fix: The RADIO_SetupAGC function had a bug where the disable parameter was ORed to the same bit position as listeningAM, effectively ignoring the disable flag. This caused the AGC to get stuck in wrong states during mode transitions.

AM +6dB post-demod gain: BK4819 REG_43 bit 2 is now enabled in AM mode, adding 6dB gain after FM demodulation. AM signals are inherently weaker than FM at the demodulator output, so this boost makes weak AM stations (like airband) noticeably more audible. The gain is automatically disabled when switching back to FM.

Squelch in AM mode uses the original BK4819 hardware squelch with all three detection methods (RSSI + noise + glitch). This was found to work better than software-based or RSSI-only approaches after extensive testing.

Improved AM Fix (from upstream)

Three improvements to the am_fix.c module that reduces AM demodulator saturation/clipping. The original algorithm structure, gain table, and target RSSI (-89dBm) are preserved: 4-sample RSSI sliding window, adaptive hysteresis, and slower gain recovery to prevent pumping artifacts.

Flashing the Firmware

1. Open https://whosmatt.github.io/uvmod/ in Chrome or Edge.
2. Turn off the radio.
3. Press and hold the PTT button, then turn on the radio while still holding PTT. The flashlight should turn on while the screen stays dark — the radio is now in bootloader mode.
4. Connect the programming cable (Baofeng/Kenwood type USB serial cable) to the radio.
5. Click "Flash directly" on the UVMOD page.
6. Select the firmware.packed.bin file from the build output.
7. Select the COM port and click Connect.
8. Wait for the process to finish. Your settings should remain intact.

Building from Source

Windows (Recommended)

1. Install ARM Toolchain

Download and install gcc-arm-none-eabi-10.3-2021.10-win32.exe from ARM Developer. Default install path: C:\Program Files (x86)\GNU Arm Embedded Toolchain\10 2021.10\

2. Install GNU Make

Download and install gnu_make-3.81.exe from GnuWin32. Default install path: C:\Program Files (x86)\GnuWin32\

3. Install Python 3

Download from python.org. During installation, check "Add python.exe to PATH". After install:

python -m pip install crcmod

4. Build

Edit win_make.bat and verify the three PATH lines match your install locations:

@set "PATH=C:\Users\YOUR_USER\AppData\Local\Programs\Python\Python3XX;%PATH%"
@set "PATH=C:\Users\YOUR_USER\AppData\Local\Programs\Python\Python3XX\Scripts;%PATH%"
@set "PATH=C:\Program Files (x86)\GNU Arm Embedded Toolchain\10 2021.10\bin;%PATH%"
@set "PATH=C:\Program Files (x86)\GNU Arm Embedded Toolchain\10 2021.10\arm-none-eabi\bin;%PATH%"
@set "PATH=C:\Program Files (x86)\GnuWin32\bin;%PATH%"

Then run:

win_make.bat

Output files: firmware.bin and firmware.packed.bin

Common issues:

• 'make' is not recognized — GnuWin32 not installed or not in PATH
• 'arm-none-eabi-gcc' not found — ARM toolchain not installed or PATH mismatch in win_make.bat
• 'python' not recognized — Python not in PATH. Find your Python install location and update the PATH in win_make.bat
• PYTHON NOT FOUND, *.PACKED.BIN WON'T BE BUILT — Python PATH not set before make runs. Ensure Python PATH lines are at the top of win_make.bat

Linux (Ubuntu/Debian)

sudo apt update
sudo apt install -y git make python3 python3-pip gcc-arm-none-eabi
pip3 install crcmod

git clone https://github.com/takyonxxx/uv-k5-firmware-custom.git
cd uv-k5-firmware-custom
make

Linux (Arch/Manjaro)

sudo pacman -S git make python python-pip arm-none-eabi-gcc arm-none-eabi-newlib
pip install crcmod

git clone https://github.com/takyonxxx/uv-k5-firmware-custom.git
cd uv-k5-firmware-custom
make

macOS

brew install git python3 armmbed/formulae/arm-none-eabi-gcc
pip3 install crcmod

git clone https://github.com/takyonxxx/uv-k5-firmware-custom.git
cd uv-k5-firmware-custom
make

Docker (any platform)

git clone https://github.com/takyonxxx/uv-k5-firmware-custom.git
cd uv-k5-firmware-custom
./compile-with-docker.sh

On Windows use compile-with-docker.bat instead.

Modified Files Summary

Code Analysis

For a detailed breakdown of flash/RAM usage, per-function sizes, feature flag costs, and recommendations on what can be disabled to free up space, see ANALYSIS.md.

For a developer-oriented overview of the code architecture, source tree, execution flow, and key subsystems, see DEVELOPER.md.

Credits

This firmware is built upon the work of:

• DualTachyon — original open firmware reverse engineering
• OneOfEleven — AM fix, fast scanning, and many improvements
• fagci — spectrum analyzer
• egzumer — merged firmware with additional features
• takyonxxx — menu simplification, auto demodulation (airband AM, HF USB), AM demod improvements (AGC fix, +6dB gain), FM indicator on main screen, TX unlock

License

Apache License 2.0 — see LICENSE.