I am having the same problem! I have a ticket opened on this. I have a BIG IP 3900 that I am using to document the downgrade from 10.2 to 9.4.8 process and also to document the 9.4.8 to 10.0.1 process. I have the downgrade working flawlessly however I can NOT get an upgrade from 9.4.8 to 10.0.1 to work! Every single time I end up with a BIG IP with no OS, well a very limited Unix OS. At that point I have to install the OS from a thumb drive. I need to have a working process of upgrading 9.4.8 to 10.0.1 and nothing seems to work. The process I am doing is listed below.
1) I copied BIGIP-10.0.1.283.0.iso to /shared/images
2) Used "im BIGIP-10.0.1.283.0.iso" to install the images2disk command
3) Issued this command " image2disk --instslot=HD1.1 --format=volumes BIGIP-10.0.1.283.0.iso"
These directions I got from this link:
https://support.f5.com/kb/en-us/products/big-ip_ltm/releasenotes/product/relnotes_10_0_1_ltm.html
As stated I have a ticket open on this issue. If I find out how to do this I will post it.
Nimbostratus