This might not be of interest to anyone, but just in case…
The GDS-3000 scopes were launched a decade or so ago, with a choice of 2 and 4 channel models at 150Mhz/250Mhz/350Mhz up to 5GS/s and 500Mhz up to 4GS/s. The GDS-3152 was the bottom of the range model (150Mhz 2 channel), but it still offered 1 x 2.5GS/s or 2 x 1.25GS/s.
The range was also sold under the Iso-Tech brand with IDS rather than GDS model naming, but the same numbering scheme.
All except the 500Mhz models seem to have been discontinued some time back. I suspect that the 500Mhz has slightly different hardware, but that the lower models are all essentially the same (possibly with an extra ADC in the 2-channel 350MHz). There was no bandwidth upgrade option AFAIK, so if you had a 150 or 250Mhz model you were stuck there.
However these run an old Linux variant, with telnet available, and looking around it seems there's a 1-byte file in the /home/dso folder which determines the model and bandwidth. The value of this byte appears to correlate to models as follows (though I've only been able to test the first 4):
00 : GDS-3152
01 : GDS-3252
02 : GDS-3352
03 : GDS-3502
04 : GDS-3154
05 : GDS-3254
06 : GDS-3354
07 : GDS-3504
I tried editing it on an Iso-tech IDS-3152 and was able to change the reported model to IDS-3252 or IDS-3352.
More importantly : with the latter it was pretty much flat out to 350Mhz with the -3 dB point just past 400MHz. The decent sample rate makes this interesting compared to similar hacks on some other scopes.I was also able to change it to the ‘500Mhz’ IDS-3502, and it reported as such but there was no actual improvement over the 350Mhz config.
The current firmware has telnet access enabled; if networking is set up (Utility button) it's easy to get command line access, for example:
telnet 172.16.5.195 23
Log in as root (the password is the same on more recent GW Instek scopes so can be readily found by searching this forum...)
First make a backup copy of the bandwidth conf file, more out of good habit than necessity:
cp /home/dso/bwconf /home/dso/bwconf.bak
Then change the model by overwriting the content with the byte value above. In this case I want the 2 channel 350Mhz, which is GDS-3352 and byte 02:
echo -n -e \\x02 > /home/dso/bwconf
Finally power the scope off and back on.
Tested on an IDS-3152, firmware 1.29. YMMV, you may brick your scope, etc.