No more GPS locks after flashing modified (resized) image

Hi all,

I have been working with the reach modules for about a year now. I have made it work with the help of some modifications provided by rtklibexplorer (rtklibexplorer.wordpress.com) to the RTKLIB and it all worked well. The only thing was that I needed to upload multiple files to the reach modules (Edison) after flashing them with the standard reach v1.2 firmware. So I tried to make my own image by modifying the contents of the hdd image (edison-image-edison.ext4) by mounting it in a Linux system and copying my files to it and modifying some of the existing files (configurations etc). The size of the image file was just not enough to contain all my files and I noticed that the root (/) file system on the Edison was somewhat larger (about 1100Mb) after the image was flashed to it so I resized the image file using resize2fs to 1100Mb.

After flashing the reach module with my image all seemed ok. All files were there and the receiver started properly. However, I cannot get any lock anymore on the GPS satellites, only on the GLONASS sats. Here is an output of the ‘sat’ command in rtkrcv after running for some time:

SAT C1 L1 L2  Fix1  Fix2  Sl1  Sl2  Lock1  Lock2 Rj1 Rj2  P1Res P2Res  L1Res  L2Res    Az   El
G02 OK  -  -     -     -    0    0   -150      0   0   0  0.000 0.000 0.0000 0.0000 307.8 30.8
G03 OK  -  -     -     -    0    0   -150      0   0   0  0.000 0.000 0.0000 0.0000 106.9 26.5
G06 OK  -  -     -     -    0    0   -150      0   0   0  0.000 0.000 0.0000 0.0000 261.8 59.6
G07 OK  -  -     -     -    0    0   -150      0   0   0  0.000 0.000 0.0000 0.0000 169.2 23.3
G09 OK  -  -     -     -    0    0   -150      0   0   0  0.000 0.000 0.0000 0.0000 221.9 74.7
G19  -  -  -     -     -    0    0   -150      0   0   0  0.000 0.000 0.0000 0.0000 236.2 13.1
G22  -  -  -     -     -    0    0   -150      0   0   0  0.000 0.000 0.0000 0.0000 109.7 10.3
G23 OK  -  -     -     -    0    0   -150      0   0   0  0.000 0.000 0.0000 0.0000  69.8 60.0
R04 OK OK  -   FIX     -    7    0   3855      0 3593   0  0.000 0.000 0.0000 0.0000  52.8 63.3
R05 OK OK  -   FIX     -    5    0   7662      0   0   0 -562.960 0.000 3.1314 0.0000 291.0 51.2
R14 OK OK  - FLOAT     -  118    0   -147      0 3593   0 -1168.351 0.000 2.4221 0.0000 113.2 34.8
R19 OK OK  - FLOAT     -  107    0   -148      0   0   0 80.631 0.000 2.1862 0.0000 209.9 16.1
R20 OK OK  -   FIX     -    8    0   5781      0   0   0 -22.472 0.000 4.0739 0.0000 266.4 43.6
R21 OK OK  - FLOAT     -   29    0    -76      0   0   0 -154.518 0.000 1.6384 0.0000 329.3 25.9
120  -  -  -     -     -    0    0   -150      0   0   0  0.000 0.000 0.0000 0.0000 206.6 26.9

As you can see, the GLONASS sats are locked and some even in FIX mode already. The GPS sats are getting the C1 signal, but nothing else happens.

I have reflashed the original reach v1.2 image to the unit and manually uploaded my modifications (that worked before I flashed my own image) but the GPS sats still don’t get a lock. I can imagine I overwrote some essential data (bios or alike) by trying to flash a larger image.

Now, the question is: how can I reset the whole unit to factory defaults? Apparently simply flashing the reach v1.2 image doesn’t work.

Please help!

Regards,
Dimitri

A shot in the dark: Instead of it being a problem with flashing the Edison, could this be fixed by changing some setting in the uBlox chip?