@RespawnedFluff That silly question about the RTC battery got into the hot network questions list. That's why it has got a high score. I might argue that it should be sent to SuperUser.
@jippie Know any tricks to make an MTD partition that's not accessible (i/e/ mem range that's not partitioned, basically) touchable from userspace? And then, to make it more fun: Without recompiling the kernel?
Compiling the kernel killed the second of my four available boards
Need to start being careful now
Turns out the memory range I found may be "default defined values", in stead of the actual env, because after the MTD0 partition, but before the MTD1 partition there's some 700kByte of unpartitioned memory and from some vars I suspect the first secotor of that space to be the actual ENV
It's not often you see Forrest Mims III cited in an academic journal...
OK, couple of dumb questions:
1. Switching regulator circuit is failing. It's an external-FET type. Under what scenarios does the regulator switch fail rather than the FET?
2. The circuit is "working" in the sense that the FB pin is driven to the expected voltage. But the output voltage is only 100 mV above V_FB instead of 1.5x V_FB. Normally I'd think this means one of the resistors in the feedback divider has failed (either the upper one is nearly-shorted or the lower one is nearly open). But both ohm out (in-circuit) at roughly the expected value. Any other ideas what to check?
Also, there's a lot of ways that a smps can fail besides the FET. Could be the controller (check the control signal to the FET). Could be resistor issues. Could be a short. Could even be a cap (but again, that would probably be a short).
So about the best I can give you is to tell you to check for hot spots, check your resistances, scope out HG and LG, and test voltages a some points around the circuit.