# Frequently Asked Build Questions This page covers questions about building QMK. If you haven't yet done so, you should read the [Build Environment Setup](getting_started_build_tools.md) and [Make Instructions](getting_started_make_guide.md) guides. ## Can't Program on Linux You will need proper permissions to operate a device. For Linux users, see the instructions regarding `udev` rules, below. If you have issues with `udev`, a work-around is to use the `sudo` command. If you are not familiar with this command, check its manual with `man sudo` or [see this webpage](https://linux.die.net/man/8/sudo). An example of using `sudo`, when your controller is ATMega32u4: $ sudo dfu-programmer atmega32u4 erase --force $ sudo dfu-programmer atmega32u4 flash your.hex $ sudo dfu-programmer atmega32u4 reset or just: $ sudo make ::dfu Note that running `make` with `sudo` is generally ***not*** a good idea, and you should use one of the former methods, if possible. ### Linux `udev` Rules On Linux, you'll need proper privileges to access the MCU. You can either use `sudo` when flashing firmware, or place these files in `/etc/udev/rules.d/`. **/etc/udev/rules.d/50-atmel-dfu.rules:** ``` # Atmel ATMega32U4 SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2ff4", MODE:="0666" # Atmel USBKEY AT90USB1287 SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2ffb", MODE:="0666" # Atmel ATMega32U2 SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2ff0", MODE:="0666" ``` **/etc/udev/rules.d/52-tmk-keyboard.rules:** ``` # tmk keyboard products https://github.com/tmk/tmk_keyboard SUBSYSTEMS=="usb", ATTRS{idVendor}=="feed", MODE:="0666" ``` **/etc/udev/rules.d/54-input-club-keyboard.rules:** ``` # Input Club keyboard bootloader SUBSYSTEMS=="usb", ATTRS{idVendor}=="1c11", MODE:="0666" ``` ### Serial device is not detected in bootloader mode on Linux Make sure your kernel has appropriate support for your device. If your device uses USB ACM, such as Pro Micro (Atmega32u4), make sure to include `CONFIG_USB_ACM=y`. Other devices may require `USB_SERIAL` and any of its sub options. ## Unknown Device for DFU Bootloader If you're using Windows to flash your keyboard, and you are running into issues, check the Device Manager. If you see an "Unknown Device" when the keyboard is in "bootloader mode", then you may have a driver issue. Re-running the installation script for MSYS2 may help (eg run `./util/qmk_install.sh` from MSYS2/WSL) or reinstalling the QMK Toolbox may fix the issue. If that doesn't work, then you may need to grab the [Zadig Utility](https://zadig.akeo.ie/). Download this, find the device in question, and select the `WinUSB` option, and hit "Reinstall driver". Once you've done that, try flashing your board, again. If that doesn't work, try all of the options, until one works. ?> There isn't a best option for which driver should be used here. Some options work better on some systems than others. libUSB and WinUSB seem to be the best options here. If the bootloader doesn't show up in the list for devices, you may need to enable the "List all devices" option in the `Options` menu, and then find the bootloader in question. ## WINAVR is Obsolete It is no longer recommended and may cause some problem. See [TMK Issue #99](https://github.com/tmk/tmk_keyboard/issues/99). ## USB VID and PID You can use any ID you want with editing `config.h`. Using any presumably unused ID will be no problem in fact except for very low chance of collision with other product. Most boards in QMK use `0xFEED` as the vendor ID. You should look through other keyboards to make sure you pick a unique Product ID. Also see this. https://github.com/tmk/tmk_keyboard/issues/150 You can buy a really unique VID:PID here. I don't think you need this for personal use. - http://www.obdev.at/products/vusb/license.html - http://www.mcselec.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=92&option=com_phpshop&Itemid=1 ## Cortex: `cstddef: No such file or directory` GCC 4.8 of Ubuntu 14.04 had this problem and had to update to 4.9 with this PPA. https://launchpad.net/~terry.guo/+archive/ubuntu/gcc-arm-embedded https://github.com/tmk/tmk_keyboard/issues/212 https://github.com/tmk/tmk_keyboard/wiki/mbed-cortex-porting#compile-error-cstddef https://developer.mbed.org/forum/mbed/topic/5205/ ## `clock_prescale_set` and `clock_div_1` Not Available Your toolchain is too old to support the MCU. For example WinAVR 20100110 doesn't support ATMega32u2. ``` Compiling C: ../../tmk_core/protocol/lufa/lufa.c avr-gcc -c -mmcu=atmega32u2 -gdwarf-2 -DF_CPU=16000000UL -DINTERRUPT_CONTROL_ENDPOINT -DBOOTLOADER_SIZE=4096 -DF_USB=16000000UL -DARCH=ARCH_AVR8 -DUSB_DEVICE_ONLY -DUSE_FLASH_DESCRIPTORS -DUSE_STATIC_OPTIONS="(USB_DEVICE_OPT_FULLSPEED | USB_OPT_REG_ENABLED | USB_OPT_AUTO_PLL)" -DFIXED_CONTROL_ENDPOINT_SIZE=8 -DFIXED_NUM_CONFIGURATIONS=1 -DPROTOCOL_LUFA -DEXTRAKEY_ENABLE -DCONSOLE_ENABLE -DCOMMAND_ENABLE -DVERSION=unknown -Os -funsigned-char -funsigned-bitfields -ffunction-sections -fdata-sections -fno-inline-small-functions -fpack-struct -fshort-enums -fno-strict-aliasing -Wall -Wstrict-prototypes -Wa,-adhlns=obj_alps64/protocol/lufa/lufa.lst -I. -I../../tmk_core -I../../tmk_core/protocol/lufa -I../../tmk_core/protocol/lufa/LUFA-git -I../../tmk_core/common -std=gnu99 -include config.h -MMD -MP -MF .dep/obj_alps64_protocol_lufa_lufa.o.d ../../tmk_core/protocol/lufa/lufa.c -o obj_alps64/protocol/lufa/lufa.o ../../tmk_core/protocol/lufa/lufa.c: In function 'setup_mcu': ../../tmk_core/protocol/lufa/lufa.c:575: warning: implicit declaration of function 'clock_prescale_set' ../../tmk_core/protocol/lufa/lufa.c:575: error: 'clock_div_1' undeclared (first use in this function) ../../tmk_core/protocol/lufa/lufa.c:575: error: (Each undeclared identifier is reported only once ../../tmk_core/protocol/lufa/lufa.c:575: error: for each function it appears in.) make: *** [obj_alps64/protocol/lufa/lufa.o] Error 1 ``` ## BOOTLOADER_SIZE for AVR Note that Teensy2.0++ bootloader size is 2048byte. Some Makefiles may have wrong comment. ``` # Boot Section Size in *bytes* # Teensy halfKay 512 # Teensy++ halfKay 2048 # Atmel DFU loader 4096 (TMK Alt Controller) # LUFA bootloader 4096 # USBaspLoader 2048 OPT_DEFS += -DBOOTLOADER_SIZE=2048 ``` ## `avr-gcc: internal compiler error: Abort trap: 6 (program cc1)` on MacOS This is an issue with updating on brew, causing symlinks that avr-gcc depend on getting mangled. The solution is to remove and reinstall all affected modules. ``` brew rm avr-gcc brew rm dfu-programmer brew rm dfu-util brew rm gcc-arm-none-eabi brew rm avrdude brew install avr-gcc brew install dfu-programmer brew install dfu-util brew install gcc-arm-none-eabi brew install avrdude ``` ### avr-gcc 8.1 and LUFA If you updated your avr-gcc to above 7 you may see errors involving LUFA. For example: `lib/lufa/LUFA/Drivers/USB/Class/Device/AudioClassDevice.h:380:5: error: 'const' attribute on function returning 'void'` For now, you need to rollback avr-gcc to 7 in brew. ``` brew uninstall --force avr-gcc brew install avr-gcc@7 brew link --force avr-gcc@7 ``` ### I just flashed my keyboard and it does nothing/keypresses don't register - it's also ARM (rev6 planck, clueboard 60, hs60v2, etc...) (Feb 2019) Due to how EEPROM works on ARM based chips, saved settings may no longer be valid. This affects the default layers, and *may*, under certain circumstances we are still figuring out, make the keyboard unusable. Resetting the EEPROM will correct this. [Planck rev6 reset EEPROM](https://cdn.discordapp.com/attachments/473506116718952450/539284620861243409/planck_rev6_default.bin) can be used to force an eeprom reset. After flashing this image, flash your normal firmware again which should restore your keyboard to _normal_ working order. [Preonic rev3 reset EEPROM](https://cdn.discordapp.com/attachments/473506116718952450/537849497313738762/preonic_rev3_default.bin) If bootmagic is enabled in any form, you should be able to do this too (see [Bootmagic docs](feature_bootmagic.md) and keyboard info for specifics on how to do this).