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 ### Serial device is not detected in bootloader mode on Linux
41 Make sure your kernel has appropriate support for your device. If your device uses USB ACM, such as
42 Pro Micro (Atmega32u4), make sure to include `CONFIG_USB_ACM=y`. Other devices may require `USB_SERIAL` and any of its sub options.
44 ## Unknown Device for DFU Bootloader
46 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.
48 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.
50 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.
52 ?> 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.
54 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.
58 It is no longer recommended and may cause some problem.
59 See [TMK Issue #99](https://github.com/tmk/tmk_keyboard/issues/99).
62 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.
64 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.
67 https://github.com/tmk/tmk_keyboard/issues/150
69 You can buy a really unique VID:PID here. I don't think you need this for personal use.
70 - http://www.obdev.at/products/vusb/license.html
71 - http://www.mcselec.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=92&option=com_phpshop&Itemid=1
73 ## Cortex: `cstddef: No such file or directory`
74 GCC 4.8 of Ubuntu 14.04 had this problem and had to update to 4.9 with this PPA.
75 https://launchpad.net/~terry.guo/+archive/ubuntu/gcc-arm-embedded
77 https://github.com/tmk/tmk_keyboard/issues/212
78 https://github.com/tmk/tmk_keyboard/wiki/mbed-cortex-porting#compile-error-cstddef
79 https://developer.mbed.org/forum/mbed/topic/5205/
81 ## `clock_prescale_set` and `clock_div_1` Not Available
82 Your toolchain is too old to support the MCU. For example WinAVR 20100110 doesn't support ATMega32u2.
85 Compiling C: ../../tmk_core/protocol/lufa/lufa.c
86 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
87 ../../tmk_core/protocol/lufa/lufa.c: In function 'setup_mcu':
88 ../../tmk_core/protocol/lufa/lufa.c:575: warning: implicit declaration of function 'clock_prescale_set'
89 ../../tmk_core/protocol/lufa/lufa.c:575: error: 'clock_div_1' undeclared (first use in this function)
90 ../../tmk_core/protocol/lufa/lufa.c:575: error: (Each undeclared identifier is reported only once
91 ../../tmk_core/protocol/lufa/lufa.c:575: error: for each function it appears in.)
92 make: *** [obj_alps64/protocol/lufa/lufa.o] Error 1
96 ## BOOTLOADER_SIZE for AVR
97 Note that Teensy2.0++ bootloader size is 2048byte. Some Makefiles may have wrong comment.
100 # Boot Section Size in *bytes*
102 # Teensy++ halfKay 2048
103 # Atmel DFU loader 4096 (TMK Alt Controller)
104 # LUFA bootloader 4096
106 OPT_DEFS += -DBOOTLOADER_SIZE=2048
109 ## `avr-gcc: internal compiler error: Abort trap: 6 (program cc1)` on MacOS
110 This is an issue with updating on brew, causing symlinks that avr-gcc depend on getting mangled.
112 The solution is to remove and reinstall all affected modules.
116 brew rm dfu-programmer
118 brew rm gcc-arm-none-eabi
121 brew install dfu-programmer
122 brew install dfu-util
123 brew install gcc-arm-none-eabi
127 ### avr-gcc 8.1 and LUFA
129 If you updated your avr-gcc to above 7 you may see errors involving LUFA. For example:
131 `lib/lufa/LUFA/Drivers/USB/Class/Device/AudioClassDevice.h:380:5: error: 'const' attribute on function returning 'void'`
133 For now, you need to rollback avr-gcc to 7 in brew.
136 brew uninstall --force avr-gcc
137 brew install avr-gcc@7
138 brew link --force avr-gcc@7
141 ### 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)
142 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.
144 [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.
145 [Preonic rev3 reset EEPROM](https://cdn.discordapp.com/attachments/473506116718952450/537849497313738762/preonic_rev3_default.bin)
147 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).