[Errata] Windows upgrade to 1703 broke grub

What happened?

After windows upgrading itself to release 1703 aka. the creator update, Grub bootloader can no longer start and says error: unknown filesystem and dropped in to grub rescue shell. Windows boots up fine from firmware memu.

TL; DR

Manually doing hexediting just taught me another valuable lesson: @Windows has the worst upgrade handling.

— @cth451 July 28, 2017

  1. Prepare a USB linux live environment.
  2. Find the correct partition number, it might have been changed during upgrade.
  3. Look for grubx64.efi in your EFI system partition and use a hex editor to open it
  4. Search for /boot/grub and notice the (,gptN) where N is your original partition number for linux OS.
  5. Change N to the new parition number, save the file and reboot.

Analysis

Before upgrade, my partition scheme was:

  • sda1 fat32: EFI system parition
  • sda2 ext4: Archlinux root filesystem
  • sda4 ntfs: Windows drive C
  • sda3 ext4: AOSC OS root filesystem

Partition numbers were not exactly in physical order of data, for I shrinked Archlinux to make room for Windows installation. However after upgrade, it became:

  • sda1 fat32: EFI system parition
  • sda2 ext4: Archlinux root filesystem
  • sda3: Windows drive C
  • sda4: Windows recovery environment
  • sda5: AOSC OS root filesystem

So what did windows do down there? It shrinked drive C and made a little recovery partition, then re-sorted the partition numbers. However grub bootloader looks for partitions by partition number. It tried parition 3 (which was a valid linux filesystem), but it’s an ntfs now.

This partition number is hardcoded into the bootloader efi image, so we need to manually hexedit it.

大阪

梅田

A photo of the Yodo-gawa (淀川) from the skyscrapers with the old DSLR Canon 50D. Juusou-suji (十三筋) and Hankyu railways are visible in this picture.

EXIF:
Camera   = Canon EOS 50D
Lens     = EF-S 17-85mm f/4-5.6 IS USM
ISO      = 100
Aperture = f/11
Exposure = 30"
Shot from 梅田スカイビル 空中庭園

天満橋

A shot of the only double decked bridge in Osaka. Taken with my Xperia Z5 on the cruise ship during sunset.

天満橋 Geotag: 小川

Cities of Minneapolis and Duluth plus wide angles

Minneapolis

First of all, the skyline of Minneapolis on MN-65 northbound. It is a beautiful city yet I haven’t post any shots of the city itself, so here is one.

Minneapolis City Skyline
Minneapolis City Skyline

The Minnehaha falls is within the city bound among private residences. Too young, too simple, sometimes naive. Continue reading Cities of Minneapolis and Duluth plus wide angles

Lake superior and sunset

Lake Superior – Sugarloaf Cove

Position: 47°29’11″N 90°58’59″W

Cobblestone underwater. Taken on sugarloaf cove beach with waterproof Xperia Z5.
Cobblestone underwater on sugarloaf cove beach with waterproof Xperia Z5.

I took this photo with the waterproof Xperia upside down with camera underwater. Not exactly what I expected but still amazing enough to see colorful cobblestone underwater.

Colorful cobblestones on the beach of Lake Superior
Colorful cobblestones on the beach of Lake Superior

Yet another regular collection of colorful stone beach.

Lake Mille Lacs

Position: 46°10’52″N 93°43’42″W

Lake Mille Lacs, partially frozen. Taken on a trail 2m from the shore.
Lake Mille Lacs, partially frozen. Taken on a trail 2m from the shore.

This one is pretty off-road on the side of a trail beyond Indians point. Cold, but beautiful.

Minnesota Route 1

Sunset on MN-1 westbound
Sunset on MN-1 westbound

Unfortunately I lost Geo-tag in this photo… So I don’t know the precise location on the road.

Minneapolis food journal?!

So it is spring break, aka. time for playing around. Apart from plenty of iterative integral assignments that are due after the spring break assigned by Tullia, we are travelling (and ingressing) in Minnesota this time. This is just a brief food journal, and I guess these courses are worth trying.

Food we had at the Ecuadorian food restaurant Chimborazo:

Seco De Carne, beef tender with rice.
Seco De Carne, beef tender with rice.

Seco de carne is over satisfying and hearty. Taste of rice is pretty unique, a little bit sour and juicy, which is not regular Chinese or Japanese way of cooking. I don’t know how they prepared it but it turns out very nice. I didn’t had a chance to taste the “Chaulafan” (sounds like “超辣饭”, super spicy rice bowl but not actually spicy at all) ordered by Jeff and other guys, but I took the picture anyway. Continue reading Minneapolis food journal?!

Goodbye, chunky. Hi, Blender! (with the Interior Of Dat Triangle)

This would be one of my last frames of Minecraft renderworks with chunky. I will be switching to blender, an open source modeling software that supports GPU ray tracing with CUDA and allows tweaks to model before performing actual (now night-long) rendering.

Chunky is still pretty straightforward to newbie CG makers, written in java that virtually runs everywhere, but it does not support GPU rendering, and java multi-threading overhead made it even worse.

Blender, on the other hand, needs a few hours to setup but provides far more precise control over elements, vertices, edges and fancy stuff. Cropping down map portions out of the camera view, customize torch light color, removing specific blocks, render entities with actual motion…

So… Goodbyeさようなら, chunky. Hi, Blender!

I might still recommend chunky for those who want to have a sip of minecraft rendering, but for more complex terrain and huge creations, use blender.

Here’s the downscaled rendered frame, but you can still find full resolution on deviant art.


Rendering Specs:

Rendering time: 1.57 days
Threads: 3
Original dimensions: 4000x4000
Downscaled dimensions for uploading: 2000x2000