These BIOS firmware modded two modules

• XA61200OverclockPeim
• XA61200OverclockShellCommand

the XA61200OverclockPeim module execute in early PEI stage and read overclock settings from EFI Variable. If EFI Variable LsOcConf is valid and overclock is enabled, CPU core voltage and Main Clock frequency will be set here.

the XA61200OverclockShellCommand register a overclock command in EFI shell, provide command options in chapter #Usage

UDK2018_3A6000-7A2000_Desktop_EVB_V4.0.05636-stable202311_dbg-overclock.fd is recommended to use

• Loongson-XA61200-UDK2018-V4.0.05494-stable202305-overclock-sa.bin: This BIOS included overclock modding and support sa voltage adjustment
• Loongson-XA61200-UDK2018-V4.0.05494-stable202305-overclock.bin: This BIOS included overclock modding, only support core voltage adjustment
• Loongson-XA61200-UDK2018-V4.0.05494-stable202305.bin: This BIOS is the original backup of my board
• UDK2018-3A6000-7A2000_EVB_V4.0.05634_prestable2311dbg-overclock.fd: This BIOS is the 2023/11-5634 version with overclock modding
• UDK2018-3A6000-7A2000_EVB_V4.0.05634_prestable2311dbg-overclock-v2.fd: This BIOS is the 2023/11-5634 version with advanced clock and overclock modding
• UDK2018_3A6000-7A2000_Desktop_EVB_V4.0.05636-stable202311_dbg-overclock.fd: This BIOS is the 2023/11-5636 version with advanced clock and overclock modding

0. backup your BIOS via SPI Flash Programmer
1. Format a USB drive with FAT32 partition
2. Copy BIOS firmware to the USB drive
3. Insert your USB drive, power on motherboard
4. Enter BIOS setup, select Security - Firmware Update, and select the firmware you desire to flash
5. Hit enter and wait 2-3 minutes

You can use help overclock in UEFI Shell to get help message

Configure XA61200 overclock settings.
 
overclock -p
overclock -e 1
overclock -vcore 1200
overclock -vsa 1200
overclock -f 2700
overclock -ndiv 7
overclock -nmode 0
overclock -htdiv 2
overclock -htmode 0
 
  -p          - Print overclock settings.
  -e          - Enable/Disable overclock settings.
  -vcore      - Set CPU core voltage (mV).
  -vsa        - Set CPU SA voltage (mV).
  -f          - Set CPU Main Clock frequency (MHz).
  -ndiv       - Set Node0_freq_ctrl register.
  -nmode      - Set freqscale_mode_node register.
  -htdiv      - Set HT_freq_scale_ctrl register.
  -htmode     - Set freqscale_mode_HT register.
  .
 
NOTES:
  1. Voltage(Core and SA) must between 1000 - 1350 mV
  2. Frequency must between 2500 - 3200 Mhz
  3. Use '-e 1' to enable overclock, '-e 0' to disable overclock
  4. Overclock settings will store in EFI variable
     If your settings make motherboard stop working, try erase NVRAM
  5. '-nmode' and '-htmode' can be '0' or '1'
     '0' means (n+1)/8
     '1' means 1/(n+1)

Then you can overclock your CPU like below. These values are for demo purposes only and are NOT GURANTEE TO WORK.

# enable overclock
Shell> overclock -e 1

# disable overclock
Shell> overclock -e 0

# set overclock frequency (Mhz)
Shell> overclock -f 2800

# set overclock core voltage (mV)
Shell> overclock -vcore 1230

# set overclock sa voltage (mV)
Shell> overclock -vsa 1200

# set node clock div
Shell> overclock -ndiv 6

# print current overclock settings
Shell> overclock -p
Overclock status: ENABLE
Overclock Main clock: 2800 Mhz
Overclock Core voltage: 1230 mV
Overclock SA voltage: 1200 mV
Overclock Node clock div: 6
Overclock Node clock mode: (n+1)/8
Overclock Node clock: 2450 Mhz
Overclock HT clock div: 3
Overclock HT clock mode: (n+1)/8
Overclock HT clock: 1225 Mhz

If you setup wrong parameters and your motherboard not able to boot, then NVRAM partition in BIOS must be erased

A convenient method is switch to backup BIOS via jumper J8 and re-flash your main BIOS.

0. shutdown motherboard.
1. copy BIOS firmware in FAT32 formated USB drive
2. toggle jumper J8 from 1-2 to 2-3, J8 is behind VGA port
3. push the power button and your motherboard will boot from "backup BIOS"
4. press F2 and enter Setup menu
5. toggle jumper J8 from 2-3 to 1-2
6. select Security - Firmware Update and select the BIOS you wanna flash.

or just open the main BIOS socket U10 and program it with SPI flash programmer like CH341A