1 # Frequently Asked Build Questions
3 This page covers questions about building QMK. If you have not yet you should read the [Build Environment Setup](getting_started_build_tools.md) and [Make Instructions](make_instructions.md) guides.
5 ## Can't program on Linux
6 You will need proper permission to operate a device. For Linux users see udev rules below. Easy way is to use `sudo` command, if you are not familiar with this command check its manual with `man sudo` or this page on line.
8 In short 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 But to run `make` with root privilege is not good idea. Use former method if possible.
21 It is no longer recommended and may cause some problem.
22 See [TMK Issue #99](https://github.com/tmk/tmk_keyboard/issues/99).
25 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.
27 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.
30 https://github.com/tmk/tmk_keyboard/issues/150
32 You can buy a really unique VID:PID here. I don't think you need this for personal use.
33 - http://www.obdev.at/products/vusb/license.html
34 - http://www.mcselec.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=92&option=com_phpshop&Itemid=1
37 On Linux you need proper privilege to access device file of MCU, you'll have to use `sudo` when flashing firmware. You can circumvent this with placing these files in `/etc/udev/rules.d/`.
39 **/etc/udev/rules.d/50-atmel-dfu.rules:**
42 SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2ff4", MODE:="0666"
43 # Atmel USBKEY AT90USB1287
44 SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2ffb", MODE:="0666"
46 SUBSYSTEMS=="usb", ATTRS{idVendor}=="03eb", ATTRS{idProduct}=="2ff0", MODE:="0666"
49 **/etc/udev/rules.d/52-tmk-keyboard.rules:**
51 # tmk keyboard products https://github.com/tmk/tmk_keyboard
52 SUBSYSTEMS=="usb", ATTRS{idVendor}=="feed", MODE:="0666"
56 ## Cortex: cstddef: No such file or directory
57 GCC 4.8 of Ubuntu 14.04 had this problem and had to update to 4.9 with this PPA.
58 https://launchpad.net/~terry.guo/+archive/ubuntu/gcc-arm-embedded
60 https://github.com/tmk/tmk_keyboard/issues/212
61 https://github.com/tmk/tmk_keyboard/wiki/mbed-cortex-porting#compile-error-cstddef
62 https://developer.mbed.org/forum/mbed/topic/5205/
65 ## 'clock_prescale_set' and 'clock_div_1' not available
66 Your toolchain is too old to support the MCU. For example WinAVR 20100110 doesn't support ATMega32u2.
69 Compiling C: ../../tmk_core/protocol/lufa/lufa.c
70 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
71 ../../tmk_core/protocol/lufa/lufa.c: In function 'setup_mcu':
72 ../../tmk_core/protocol/lufa/lufa.c:575: warning: implicit declaration of function 'clock_prescale_set'
73 ../../tmk_core/protocol/lufa/lufa.c:575: error: 'clock_div_1' undeclared (first use in this function)
74 ../../tmk_core/protocol/lufa/lufa.c:575: error: (Each undeclared identifier is reported only once
75 ../../tmk_core/protocol/lufa/lufa.c:575: error: for each function it appears in.)
76 make: *** [obj_alps64/protocol/lufa/lufa.o] Error 1
80 ## BOOTLOADER_SIZE for AVR
81 Note that Teensy2.0++ bootloader size is 2048byte. Some Makefiles may have wrong comment.
84 # Boot Section Size in *bytes*
86 # Teensy++ halfKay 2048
87 # Atmel DFU loader 4096 (TMK Alt Controller)
88 # LUFA bootloader 4096
90 OPT_DEFS += -DBOOTLOADER_SIZE=2048