Two questions concerning zipped images

USB Image Tool support forum
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whitecat
Posts: 3
Joined: Sun Nov 01, 2020 9:51 pm

Two questions concerning zipped images

Post by whitecat »

Hi there,

thank you for this handy tool I'm currently testing in order to read/write images from a Raspberry Pi. So far it looks very good and I'm probably going to replace all the other imaging tools I've used so far with your tool.

Two questions (or better: One question and a suggestion):

1. In order to reduce the image size I usually zip my images. If I do this with 7-zip, everything works fine, these images could be restored later without problems. However, if I do this with the builtin zipper from Windows 8.1 (Pro, 64 bit), the zip file cannot be read anymore by USB Image tool. Instead, an error message appears: "Could not access the image file (Code: 0)!"Is this a Windows problem or does USB Image tool expect a certain type of zip files Windows isn't able to create?

2. The restore function of USB Image Tool shows only files with the extension .imz when I select the file type "Compressed (zip) image files". Here it would be very useful if also files with the extension .zip were shown here as e.g. the Raspberry OS images come with this extension. Zipped files with the extension .zip work nevertheless if I choose "All files", but then I see all the other files in the directory.

whitecat
Last edited by whitecat on Fri Jun 03, 2022 8:14 am, edited 1 time in total.
Alex
Site Admin
Posts: 267
Joined: Fri Jul 29, 2011 11:59 pm

Re: Two questions concerning zipped images

Post by Alex »

1. I need to investigate that. For my understanding: You created a raw img file and zipped that later on with the Microsoft built-in zipper? I will try this with Windows 10 zipper within the next days. USB Image Tool uses the minizip zip implementation from zlib. Maybe there is some kind of incompatibility.

2. I will put that on the list for the next version.

Thanks for the feedback!
whitecat
Posts: 3
Joined: Sun Nov 01, 2020 9:51 pm

Re: Two questions concerning zipped images

Post by whitecat »

1. Exactly (but with Windows 8.1 Pro, not any of the Windows 10 flavours).

2. :D

whitecat
whitecat
Posts: 3
Joined: Sun Nov 01, 2020 9:51 pm

Re: Two questions concerning zipped images

Post by whitecat »

Hi there,

one more observation:

3. If I choose "Backup" in order to create a compressed image file of type "Compressed gzip image file", an error appears: "Compressed images can only be created up to 4 GiB!" If I click on the "Ok" button the "Saving image" progress bar in the lower left corner gets stuck at 0%. If I click "Cancel", a warning appears: "An IO operation is in progress! [...]" If I click on "Yes", the program will not be closed. If I try to close the window, the same error appears, if I click on "Yes" again, the programm finally terminates.

Saving to a .zip/.imz file works as it should, as does restoring from it.

(Tested with an 8 GB SD card and an image taken from a Raspberry Pi 3B.)

whitecat
Alex
Site Admin
Posts: 267
Joined: Fri Jul 29, 2011 11:59 pm

Re: Two questions concerning zipped images

Post by Alex »

2. & 3. have been fixed/implemented with version 1.82. For 1.: I did some research and this behaviour is related to the Windows built in zip routines. For zip-files estimated larger than 2 GiB, Windows uses Deflate64 compression, which is not supported by zlib (see zlib FAQ https://zlib.net/zlib_faq.html#faq40). zlib library is used for zip/imz and gzip functionality in USB Image Tool. 7-zip for example allows to choose the compression algorithm and uses Deflate as default also for larger files.
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