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2023/03/09 Solar Monitoring Bit Flip Rabbithole
π 2023-03-09 01:01 in Linux, Linuxha
My own "I'm just going to spend 5mn to fix this" story, that lasted over 6H.

  • Power outage rebooted one of my energy monitors and it's now counting one of my solar arrays backwards because of an apparent bit flip in the flash (it's an old device)
  • 10 days later I'm finally home long enough to look at this, I "just" need to connect to it via some windows only app, connect via the serial port and reprogram the lost/corrupted settings
  • Ah, but my only desktop/windows machine left in the house blew a capacitor on its motherboard recently, and I haven't been able to justify the time to fix it (that would be a rabbit hole on its own and I know this), so I can't use that
  • unfortunately that one device only works with a real serial port, not any USB-serial adapters I've been able to try (and I have 4 different brands/chips), so that prevents use of any of my laptops
  • oh, wait, I do have a much older thinkpad with a docking station that has a _real_ serial port, let's try this.
  • ok, it boots, but the windows XP partition gives some "NTLDR missing". I haven't used it in some 15 years, so I wouldn't know
  • ok, let's boot linux, ubuntu oneiric, oh my. Virtualbox won't work, modules are broken, I try a few of the kernels, a mix of 32bit kernels with himem for the 8GB of RAM, and some x64 kernels with 32bit userspace. None of them want to build working virtualbox modules.
  • apt-get install is of course broken with a weird dependency chain, not going to go to _that_ rabbithole either (see, I've learned from previous times)
  • maybe I can make that WXP partition boot again? Ok, I'll skip details on how that ends up in cleaning half my bedroom while looking for old boot/recovery CDs (BartPE, UBCD, etc...), another 1.5h rabbithole
  • eventually get the boot CDs, they also BSOD during boot, look in bios, change the SATA support from AHCI to compatible, that fixes it
  • fast forward through some "details", boot WXP recovery console, apply "fixboot" and "fixmbr" which of course removes the install-mbr bootloader I had installed to dual boot WXP and llinux, and was not present on my linux recovery CDs
  • eventually boot some linux recovery that allows me to decrypt the linux partition (luksopen), chroot into it because it's not the same binary format, and install-mbr -t 54 -v -e 14FA -p 2 -is /dev/sda
  • eventually get WXP to boot, for some reason the wireless support does not work anymore and can't connect. Ok, use ethernet instead and everything is so old that none fhe web browsers work, because everything is https and the ciphers are all incompatible with older browsers now
  • retrieve the device windows software from my normal laptop, copy it over, install it, it runs, uses the real serial port on the ultrabay, and connects to my power monitor. I revert the broken settings on the device over serial, and save them.
  • SUCCESS!

    That only took about 6H, why it it dark outside? Oh, it's past midnight. What was I doing before that?


    More pages: March 2023 July 2014 December 2013 November 2013 January 2013 November 2011 August 2011 July 2011 March 2011 August 2010 June 2010 March 2010 February 2010 December 2009 November 2009 August 2009 May 2009 March 2009 March 2004

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