GHI Bootloader

The GHI Bootloader is used to update the firmware on our devices. It is the first program to run and unless the device specific LDR pins are set (see device documentation for details), it will execute the firmware on the device (if present).

The bootloader communicates over a USB virtual serial port and a regular serial port. The interface used is controlled by a MODE pin. See your device specifications for details on interface configuration and selection and which version of the bootloader it runs.

Tip

If you are running Windows 7 or Windows 8, you must install drivers for the bootloader to appear in Windows. See "USB Drivers" in the downloads section.

Bootloader v2

All commands and results are terminated with CR and LF (\r\n). "OK." will be sent after each successful command.

On startup, a banner is sent that is terminated by "OK.". Once the banner is received, you are free to enter any of the case-insensitive single-character commands described below.

Most commands require confirmation. Send Y or y followed by a new-line to proceed or anything else to cancel.

  • V: returns the current version.
  • N: returns the current device type.
  • E: erases all user sectors of the device.
  • R: runs the firmware if present.
  • B: increases the baud rate in serial mode to 921,600.
  • X: upload a ghi file to the device using 1K XMODEM. Only send *.ghi files meant for your device.
  • U: upload a glb file to the device using 1K XMODEM. Only send *.glb files meant for your device.

Loading the Firmware

The individual product pages include further instructions on the firmware needed and how to set the board in the loader mode. Once you have downloaded the firmware and set the board in loader mode, use the instructions below to load the firmware.

Using TinyCLR Config

TinyCLR Config tool includes multiple features developers need to work with TinyCLR OS-enabled devices. It simplifies the firmware update and it includes options for accessing the TinyCLR firmware at runtime.

Using this tool is the recommended path; however, manual installation instructions are also included on this page. Read more on the TinyCLR Config page.

Manually Loading the Firmware

TinyCLR Config tool should be used to update the firmware. As a backup, use these instructions:

  1. Put your board in bootloader mode. Each product has a specific way to enter the boot loader.
  2. Open any terminal software, for example Tera Term.
  3. Select serial and pick the COM port associated with your board. (If unsure, check Device Manager)
  4. Press V and then enter. You will see back the boot loader version number (v2.x.x)
  5. Press U or X and then enter. Use X for firmware file type GHI and U for firmware file type GLB.
  6. Press Y to confirm then enter. You will now see CCCC...
  7. Go to File -> Transfer -> XMODEM -> Send and then check the 1K option.
  8. Select the firmware file.
  9. When the transfer is complete, reset your board.

GLB File Format

The glb files that are loaded onto devices have some additional metadata that help the bootloader function in addition to the raw data itself. The first 1,024 bytes of a glb file is the upload header. Starting from offset 0 are the below fields. The rest of the header is currently reserved.

  1. 32 bit signature number that is unique for each device.
  2. 32 bit unsigned address in flash that this image should be copied to.
  3. 32 bit unsigned length of the image to flash rounded to the nearest 1,024 bytes.
  4. 16 bit CRC-CCITT of the image.

After the upload header is the actual image to flash. If its length is not divisible by 1,024 bytes, it is padded until it is. For images that are meant to be bootable, the address in the upload header should be set to the entry point defined for the specific device. Bootable images have an additional 1,024 byte header at the beginning of the image that is used to verify the image before booting it. The boot image is also padded to the nearest 1,024 bytes. Starting from offset 0 are the below fields. The rest of the header is currently reserved.

  1. 32 bit signature number that is unique for each device.
  2. 32 bit unsigned address in flash that is the entry point the bootloader will invoke.
  3. 32 bit unsigned length of the boot image rounded to the nearest 1,024 bytes.
  4. 16 bit CRC-CCITT of the boot image bounded by the specified address and length.

Bootloader v1

Currently the Embedded Master, EMX, G120, G120E and USBizi ship with this version of the bootloader. All results are terminated with LF (\n). Commands are executed as soon as they entered without waiting for a new-line. "BL" or "Done." will be sent after each command.

On startup, a banner is sent that is terminated by "BL". Once the banner is received, you are free to enter any of the case-sensitive single-character commands described below.

  • V: returns the current version.
  • E: erases all user sectors of the device (* is sent while erasing).
  • R: runs the firmware if present.
  • B: increases the baud rate in serial mode to 921,600.
  • X: upload a file to the device using 1K XMODEM. Only send *.ghi files meant for your device. The firmware is automatically run after a successful upload.
Tip

The USB interface on Version 1.0 doesn't always work on Windows 7 and newer operating systems. Use the serial interface instead.

Upgrading GHI Bootloader v1 to v2

Some of our devices ship with v1 loader but require v2 loader to work with TinyCLR OS, such as G120.

  1. Download the bootloader file from the list below.
  2. Put your device in v1 mode (instructions are found on each product's documentation page).
  3. The PC will now detect a virtual serial (COM) device. If you need drivers, they are in the NETMF SDK.
  4. Open any terminal software, we recommend Tera Term.
  5. Select serial and pick the COM port associated with your board.
  6. Enter E and you will see back "Erase all memory! Are you sure?" now enter Y. (The bootloader is case sensitive)
  7. Enter X and you will see CCCC... showing on the terminal.
  8. Now go to File -> Transfer -> XMODEM -> Send and then check the 1K option.
  9. Select the bootloader file you have downloaded above.
  10. You will see File Transfer Finished Successfully.
  11. Change the configuration switches back to the off position and reset the board.
  12. You are now running GHI Electronics bootloader v2!

Bootloader Downloads

Most products already ship with bootloader already installed. But in case the loader needs to be reloaded, the individual product pages include instructions on how to load the bootloader. Here you can find the various bootloaders available for the various products.

FEZCLR (used on FEZ and BrainPad)

File Date Status MD5
v2.0.4 2017-08-31 Alpha 33F7FCAE266D07209C079CEA38AAB583
v2.0.3 2017-07-07 Alpha 056919694D6A5F06546F9B721AE141CE

UC2550

File Date Status MD5
v2.0.4 2018-04-05 Alpha 692FA78A161BAA2AEF17E9F85A6AF141

UC5550

File Date Status MD5
v2.0.5 2018-09-28 Alpha 9F4DB868E5501773CC52048D8085B8D6
v2.0.4 2018-04-05 Alpha 594744A52EC07CEFE6212669D33A5FE1

G120 and G120E

File Date Status MD5
v2.0.4 2017-08-31 Alpha 7052D6FFB1890987DDCC4043895788D3
v2.0.2 2017-03-07 Alpha 00ECD55A24607336863B1D61B91C3D86

G400S and G400D

File Date Status MD5
v2.0.4 2017-09-13 Alpha BD46D86D41DCD42C4FC50D27AF02E5EE
v2.0.2 2017-04-06 Alpha 81D45A8F078AA8E633C824C7BB3279DC
v2.0.1 2016-06-27 Alpha 42CD50E4105939611ABF360475EBF4E5

USBizi

File Date Status MD5
v1.0.7 144 2015-05-05 Production 853557479D8797EAB650B98E3D333DCF
v1.0.7 100 2015-05-05 Production 34D17AA5CA4E13D5447C80AB8094D064

USB Drivers

Only needed for Windows 7 and 8 since they do not automatically load drivers for the bootloader interface.

File Date Status MD5
v1.0.0 x64 2018-12-27 Production 74D66FC4236126A83CCCFE28D556F339
v1.0.0 x86 2018-12-27 Production 8BDE68132452E22B14597C0972ABA8FD
v0.6.0 x64 2017-08-31 Alpha AEDD7C00854BBF99AC3FDAB4976E1F33
v0.6.0 x86 2017-08-31 Alpha A0F487D32B882199F0A69E6CAA8DE4CB