This is the 5th sansa clipzip i'm rockboxing but i'm running into troubles now. My old clpza.bin is not accepted anymore, so i tried the instructions in the pdf, downloaded clipzip01.01.18.zip and bootloader-clipzip.sansa and ran mkamsboot.exe.
It reports succes,but when i start the rockbox utility and browse to that bin it tells me
[ERR] Original firmware unknown, please try another version. Tested Clipzipv1 versions are 1.01.1, 1.01.15, 1.01.17, 1.01.18 1.01.20, 1.01.21
I'm not sure what to do now, I never had to mess with mkamsboot.exe before if i remember correctly. I remember just putting some .bin in the root of the sansa together with the .rockbox map.
Please help, i have a new player and i want rockbox on it!
 I succeeded, the trick was to *not* use mkamsboot and provide the rockbox utility with the downloaded clpza.bin