1 # Frequently Asked Build Questions
3 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.
5 ## Can't Program on Linux
6 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).
8 An example of using `sudo`, when your controller is ATMega32u4:
10 $ sudo dfu-programmer atmega32u4 erase --force
11 $ sudo dfu-programmer atmega32u4 flash your.hex
12 $ sudo dfu-programmer atmega32u4 reset
16 $ sudo make <keyboard>:<keymap>:dfu
18 Note that running `make` with `sudo` is generally *not* a good idea, and you should use one of the former methods, if possible.
20 ### Linux `udev` Rules
21 On Linux, you'll need proper privileges to access the MCU. You can either use
22 `sudo` when flashing firmware, or place these files in `/etc/udev/rules.d/`.
24 **/etc/udev/rules.d/50-atmel-dfu.rules:**
27 SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2ff4", MODE:="0666"
28 # Atmel USBKEY AT90USB1287
29 SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2ffb", MODE:="0666"
31 SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2ff0", MODE:="0666"
34 **/etc/udev/rules.d/52-tmk-keyboard.rules:**
36 # tmk keyboard products https://github.com/tmk/tmk_keyboard
37 SUBSYSTEMS=="usb", ATTRS{idVendor}=="feed", MODE:="0666"
40 ## Unknown Device for DFU Bootloader
42 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.
44 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.
46 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 `WinUS(libusb-1.0)` option, and hit "Reinstall driver". Once you've done that, try flashing your board, again.
49 It is no longer recommended and may cause some problem.
50 See [TMK Issue #99](https://github.com/tmk/tmk_keyboard/issues/99).
53 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.
55 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.
58 https://github.com/tmk/tmk_keyboard/issues/150
60 You can buy a really unique VID:PID here. I don't think you need this for personal use.
61 - http://www.obdev.at/products/vusb/license.html
62 - http://www.mcselec.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=92&option=com_phpshop&Itemid=1
64 ## Cortex: `cstddef: No such file or directory`
65 GCC 4.8 of Ubuntu 14.04 had this problem and had to update to 4.9 with this PPA.
66 https://launchpad.net/~terry.guo/+archive/ubuntu/gcc-arm-embedded
68 https://github.com/tmk/tmk_keyboard/issues/212
69 https://github.com/tmk/tmk_keyboard/wiki/mbed-cortex-porting#compile-error-cstddef
70 https://developer.mbed.org/forum/mbed/topic/5205/
72 ## `clock_prescale_set` and `clock_div_1` Not Available
73 Your toolchain is too old to support the MCU. For example WinAVR 20100110 doesn't support ATMega32u2.
76 Compiling C: ../../tmk_core/protocol/lufa/lufa.c
77 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
78 ../../tmk_core/protocol/lufa/lufa.c: In function 'setup_mcu':
79 ../../tmk_core/protocol/lufa/lufa.c:575: warning: implicit declaration of function 'clock_prescale_set'
80 ../../tmk_core/protocol/lufa/lufa.c:575: error: 'clock_div_1' undeclared (first use in this function)
81 ../../tmk_core/protocol/lufa/lufa.c:575: error: (Each undeclared identifier is reported only once
82 ../../tmk_core/protocol/lufa/lufa.c:575: error: for each function it appears in.)
83 make: *** [obj_alps64/protocol/lufa/lufa.o] Error 1
87 ## BOOTLOADER_SIZE for AVR
88 Note that Teensy2.0++ bootloader size is 2048byte. Some Makefiles may have wrong comment.
91 # Boot Section Size in *bytes*
93 # Teensy++ halfKay 2048
94 # Atmel DFU loader 4096 (TMK Alt Controller)
95 # LUFA bootloader 4096
97 OPT_DEFS += -DBOOTLOADER_SIZE=2048
100 ## `avr-gcc: internal compiler error: Abort trap: 6 (program cc1)` on MacOS
101 This is an issue with updating on brew, causing symlinks that avr-gcc depend on getting mangled.
103 The solution is to remove and reinstall all affected modules.
107 brew rm dfu-programmer
109 brew rm gcc-arm-none-eabi
112 brew install dfu-programmer
113 brew install dfu-util
114 brew install gcc-arm-none-eabi
118 ### avr-gcc 8.1 and LUFA
120 If you updated your avr-gcc to above 7 you may see errors involving LUFA. For example:
122 `lib/lufa/LUFA/Drivers/USB/Class/Device/AudioClassDevice.h:380:5: error: 'const' attribute on function returning 'void'`
124 For now, you need to rollback avr-gcc to 7 in brew.
127 brew uninstall --force avr-gcc
128 brew install avr-gcc@7
129 brew link --force avr-gcc@7