ROM Hack Need help with .PACK Files/Nintendo 3DS Camera RomFS

[rescribe]

Hello, I have been trying to find the image assets for the effects (hearts, stars, bubbles, etc. that appear on screen) in the Nintendo 3DS camera.

Spoiler: Effects

I have decrypted/extracted the romfs from the .cia and have successfully been able to open a few files such as .arc and view the images within them using EveryFileExplorer but the file that the effects are located in is .pack format which cannot be opened.

I opened it in HXD and can see some text such as "BubB.bcptl.LZ" which is what I think I'm looking for but I cannot extract them from this file.

Spoiler: Hex

Does anyone know how to view or extract these from a .pack file?

Download to the .pack file.

 

[sentimental]

You can extract them with hex editor manually. The header format is simple.

[Header0]
00h-37h: Filename
38h-3Bh: Offset of LZ11 compressed data
3Ch-3Fh: Size of LZ11 compressed data
[Header1]
...


For example:
the 32-bit integer at 0x38 is 0x480
the 32-bit integer at 0x3C is 0x3C06

then you can copy the data from 0x480 to 0x480+0x3C06(=0x4086), save them as a new file.
There're many tools are capable to extract lz11 compressed data.
I've used nlzss to decompress this sample data.

 

[rescribe]

You can extract them with hex editor manually. The header format is simple.

[Header0]
00h-37h: Filename
38h-3Bh: Offset of LZ11 compressed data
3Ch-3Fh: Size of LZ11 compressed data
[Header1]
...


For example:
the 32-bit integer at 0x38 is 0x480
the 32-bit integer at 0x3C is 0x3C06

then you can copy the data from 0x480 to 0x480+0x3C06(=0x4086), save them as a new file.
There're many tools are capable to extract lz11 compressed data.
I've used nlzss to decompress this sample data.

Thank you for all your help! I ended up following your example and creating the files using HxD, then I used EveryFileExplorer's feature (Tools>Compression>Common Compressors Plugin>LZ11>Decompress) and this sucessfully decompressed them. Then to view and extract the .pngs I used Kukki/Kuriimu which worked perfectly. Also a note for anyone in the future, instead of manually extracting the .lz files using HxD, you can use Karameru to extract the .LZ from the .pack file.