In my last post, I wrote about how I installed a new kernel onto my old C.H.I.P. As it turned out, not long after writing that post my C.H.I.P. died. It wouldn’t respond to anything, and the heartbeat blinking LED stopped. I didn’t bother to connect a serial port to it, as I figured there was no point. My suspicion is that the flash somehow got corrupted.
Since I didn’t want to repeat the entire reflashing procedure again, only to wait for another random death, I looked into what options were available to me. As it turns out, macromorgan has done some work on the C.H.I.P and came up with a new way to flash it over on reddit.
I won’t repeat all his instructions here, as they’re clear and I was able to pretty easily follow them. With it, you have an easy way to reflash your device if it ever gets bricked again. As a bonus, you also get Debian 11 with a modern (5.x) kernel, unlike the old C.H.I.P software I previously showed. Unfortunately, there is one trade-off: you lose half your storage capacity, dropping it down to 2GB. In my case, this wasn’t a problem, and I was happy to trade some space for reliability considering how long it just lasted before.
All of that to say, if all you want is Debian 11 and a modern kernel, you can follow his guide and be done.
Unfortunately, I wanted to continue getting PPS working, and his kernel does not include the needed support, so I needed to build it again. As well, the procedure is different, being debian-based, and honestly the documentation out there is just confusing.
I was going to write a guide on it – and still might – but at the moment I have absolutely no time to, and probably won’t for some time. Some key notes:
- I was able to get PPS working for GPS time synchronization
- The kernel has been stable for going on a year now. No issues with flash or anything
- You will need to be familiar with building a Linux kernel and some embedded development. In my case, it had been a while, but after some time I figured it out thanks to the aforementioned guides
- You need to modify the dtb file (compiled from dts) to actually get the PPS driver to load and specify the pin to listen on. Much more of a pain than on a Raspberry Pi.
- In the future, and if they ever become available to buy again, I’ll be getting another Pi. Much better documentation, support for new kernels, and general ease of use as a result.
macromorgan documents some of the basics and provide some essential files on his git repo here.
chip@CHIP:~$ chronyc sourcestats -v .- Number of sample points in measurement set. / .- Number of residual runs with same sign. | / .- Length of measurement set (time). | | / .- Est. clock freq error (ppm). | | | / .- Est. error in freq. | | | | / .- Est. offset. | | | | | | On the -. | | | | | | samples. \ | | | | | | | Name/IP Address NP NR Span Frequency Freq Skew Offset Std Dev ============================================================================== GPS 9 4 123 +8.098 37.073 +18.4s 831us PPS 8 4 111 +0.002 0.322 +16ns 5613ns 220.127.116.11 7 5 103m +0.642 1.485 +1783us 984us ntp1.torix.ca 6 3 103m +0.677 1.226 +559us 813us dns3.switch.ca 6 3 103m +0.642 1.194 +679us 791us backoffice-1.incentre.net 12 5 241m +1.278 0.288 +1889us 857us