diff --git a/PlatformIO.md b/PlatformIO.md
index b2496c33..a2e31667 100644
--- a/PlatformIO.md
+++ b/PlatformIO.md
@@ -160,6 +160,7 @@ Below is a table with supported clocks for MiniCore. Defaults to 16 MHz if not s
 | 11.0592 MHz | External   | `11059200L`               |
 | 8 MHz       | External   | `8000000L`                |
 | 7.3728  MHz | External   | `7372800L`                |
+| 6 MHz       | External   | `6000000L`                |
 | 3.6864  MHz | External   | `3686400L`                |
 | 1.8432  MHz | External   | `1843200L`                |
 | 8 MHz       | Internal   | `8000000L`                |
@@ -242,6 +243,7 @@ Recommended baud rate for the particular clock speed is in **bold text**.
 | `11059200L` |         |        |  X     |        |  X     |  X     |  **X** |  X     |  X    |  X     |
 | `8000000L`  |  X      |  X     |        |  X     |        |  X     |  X     |  **X** |  X    |  X     |
 | `7372800L`  |         |        |  X     |        |  X     |  **X** |  X     |  X     |  X    |  X     |
+| `6000000L`  |         |  X     |        |  X     |        |        |  **X** |        |  X    |  X     |
 | `3686400L`  |         |        |  X     |        |  X     |  **X** |  X     |  X     |  X    |  X     |
 | `1843200L`  |         |        |        |        |  X     |  **X** |  X     |  X     |  X    |  X     |
 | `1000000L`  |         |        |        |        |        |        |        |        |       |  **X** |
diff --git a/README.md b/README.md
index 5c723e77..c003a298 100644
--- a/README.md
+++ b/README.md
@@ -65,6 +65,7 @@ Make sure you connect an ISP programmer, and select the correct one in the "Prog
 | 11.0592 MHz | External crystal/oscillator | Great clock for UART communication with no error              |
 | 8 MHz       | External crystal/oscillator | Common clock when working with 3.3V                           |
 | 7.3728 MHz  | External crystal/oscillator | Great clock for UART communication with no error              |
+| 6 MHz       | External crystal/oscillator |                                                               |
 | 4 MHz       | External crystal/oscillator |                                                               |
 | 3.6864 MHz  | External crystal/oscillator | Great clock for UART communication with no error              |
 | 2 MHz       | External crystal/oscillator |                                                               |
diff --git a/avr/boards.txt b/avr/boards.txt
index 755dcb77..5731c077 100644
--- a/avr/boards.txt
+++ b/avr/boards.txt
@@ -149,6 +149,12 @@ menu.bootloader=Bootloader
 328.menu.clock.7_3728MHz_external.build.clkpr=
 328.menu.clock.7_3728MHz_external.build.f_cpu=7372800L
 
+328.menu.clock.6MHz_external=External 6 MHz
+328.menu.clock.6MHz_external.upload.speed=57600
+328.menu.clock.6MHz_external.bootloader.low_fuses=0b1111{bootloader.cksel_bits}
+328.menu.clock.6MHz_external.build.clkpr=
+328.menu.clock.6MHz_external.build.f_cpu=6000000L
+
 328.menu.clock.4MHz_external=External 4 MHz
 328.menu.clock.4MHz_external.upload.speed=9600
 328.menu.clock.4MHz_external.bootloader.low_fuses=0b1111{bootloader.cksel_bits}
@@ -343,6 +349,12 @@ menu.bootloader=Bootloader
 168.menu.clock.7_3728MHz_external.build.clkpr=
 168.menu.clock.7_3728MHz_external.build.f_cpu=7372800L
 
+168.menu.clock.6MHz_external=External 6 MHz
+168.menu.clock.6MHz_external.upload.speed=57600
+168.menu.clock.6MHz_external.bootloader.low_fuses=0b1111{bootloader.cksel_bits}
+168.menu.clock.6MHz_external.build.clkpr=
+168.menu.clock.6MHz_external.build.f_cpu=6000000L
+
 168.menu.clock.4MHz_external=External 4 MHz
 168.menu.clock.4MHz_external.upload.speed=9600
 168.menu.clock.4MHz_external.bootloader.low_fuses=0b1111{bootloader.cksel_bits}
@@ -521,6 +533,12 @@ menu.bootloader=Bootloader
 88.menu.clock.7_3728MHz_external.build.clkpr=
 88.menu.clock.7_3728MHz_external.build.f_cpu=7372800L
 
+88.menu.clock.6MHz_external=External 6 MHz
+88.menu.clock.6MHz_external.upload.speed=57600
+88.menu.clock.6MHz_external.bootloader.low_fuses=0b1111{bootloader.cksel_bits}
+88.menu.clock.6MHz_external.build.clkpr=
+88.menu.clock.6MHz_external.build.f_cpu=6000000L
+
 88.menu.clock.4MHz_external=External 4 MHz
 88.menu.clock.4MHz_external.upload.speed=9600
 88.menu.clock.4MHz_external.bootloader.low_fuses=0b1111{bootloader.cksel_bits}
@@ -700,6 +718,12 @@ menu.bootloader=Bootloader
 48.menu.clock.7_3728MHz_external.build.clkpr=
 48.menu.clock.7_3728MHz_external.build.f_cpu=7372800L
 
+48.menu.clock.6MHz_external=External 6 MHz
+48.menu.clock.6MHz_external.upload.speed=57600
+48.menu.clock.6MHz_external.bootloader.low_fuses=0b1111{bootloader.cksel_bits}
+48.menu.clock.6MHz_external.build.clkpr=
+48.menu.clock.6MHz_external.build.f_cpu=6000000L
+
 48.menu.clock.4MHz_external=External 4 MHz
 48.menu.clock.4MHz_external.upload.speed=9600
 48.menu.clock.4MHz_external.bootloader.low_fuses=0b1111{bootloader.cksel_bits}
@@ -863,6 +887,12 @@ menu.bootloader=Bootloader
 8.menu.clock.7_3728MHz_external.bootloader.ckopt_bit=0
 8.menu.clock.7_3728MHz_external.build.f_cpu=7372800L
 
+8.menu.clock.6MHz_external=External 6 MHz
+8.menu.clock.6MHz_external.upload.speed=57600
+8.menu.clock.6MHz_external.bootloader.sut_cksel_bits=111111
+8.menu.clock.6MHz_external.bootloader.ckopt_bit=0
+8.menu.clock.6MHz_external.build.f_cpu=6000000L
+
 8.menu.clock.4MHz_external=External 4 MHz
 8.menu.clock.4MHz_external.upload.speed=9600
 8.menu.clock.4MHz_external.bootloader.sut_cksel_bits=111111