Hi @chet and welcome to the forum! Sorry to hear that things are not going as smoothly as they should.
Yes, you can manually set the shunt resistor value, but you will lose some dynamic range. In the “Control” widget in they UI (which is shown by default when you select View → Oscilloscope), select Current Range 2A:
Now, the more puzzling question is why is your target device reseting? Your device will normally be operating in Joulescope’s 18 mA range using a 1.11 Ω shunt resistor. Joulescope will autorange in 1.2 µs, max. Even if your edge rate is slow and Joulescope briefly autoranges to 180 mA (0.11 Ω) before autoranging to 2 A (0.01 Ω), the voltage drop will be 0.11 Ω * 1 A = 110 mV. Even that amount should not cause your target device to brown out.
I have some questions:
What is the approximate capacitance of your target device? For a 1 A jump, I normally recommend at least 10 µF, which is a reasonable amount normally needed for your target device to work properly even without Joulescope.
How long is your cabling and what gauge wire are you using? At 1 A, 22 gauge hook-up wire’s 53 mΩ/meter resistance can really add up. Wikipedia has a good table showing wire resistance per length.
What is the maximum voltage drop that your target can handle before reseting (likely due to brown-out reset)?