Posts Tagged ‘holux’

Holux GPSlim236 boot mode

June 18, 2007 Leave a comment

Should the urge grab you to play with firmware on these SiRFStarIII handheld GPS units, you will undoubtedly discover there is a boot mode one must enable before the 4Mbit flash chip can be read from or written to using SiRFflash.

Whilst we can send message 148 (0x94) to it from SiRFdemo to enable this mode, it’s handy to know one can also short the highlighted pads above (two gold pads enclosed in the white square border just above the label ‘C48’) whilst turning the unit on to achieve the same thing.

“PSRF100,0,38400,8,1,0” is the NMEA sentence to enable SiRF mode.
“94” is the SiRF binary code to enable boot mode.

As long as we always communicate at 38400 baud, it is perfectly possible to flash the firmware over bluetooth, and as you now know the location of the boot mode enabling pads, you can easily recover from a bad flash (eg. trying to push updated SiRF firmwares from other products onto it to enable proper SBAS support).

To put the GPSlim236 into boot mode, you’ll need : (thanks Antineutrino!)

Then to read or write the firmware to the GPSlim236, you’ll need : (thanks Antineutrino!)

Here is a backup of my old Holux V5 firmware (binary, not Motorola format):
GSW3.1.1_3.1.00.07-C23B1.00.bin (From SiRFflash, 0x00 to 0x79999)

And here is the Holux V6 firmware (binary, not Motorola format):
GSW3.2.2_3.1.00.12-SDK003P1.bin (kindly extracted by ‘brio2001’ from

And here is the Holux V7 ? firmware (binary, not Motorola format):
GSW3.2.4_3.1.00.12-SDK003P1.00a.bin (kindly extracted by ‘tsp’ from

Note the V6 firmware supposedly has better support for SBAS based DGPS, which is EGNOS for those of us in Europe. Just have to wait until September when the three birds begin transmitting non-test correction data.

Note the V7 firmware is extracted from a rev.C board and may cause problems if you flash it to a rev.B board, though at least one user has successfully done so.

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