I seems you don't have issue only with USB stick, but also with CD-ROM. In this case, could you update the bug title.
If issue is due to presence of SD card at start, why not removing SD card at start and hot-plug it after boot and before install ?
About mass memory enumeration, there are some issues since 10.10 as BIOS and some other software don't use same order (including Grub).
I seems you don't have issue only with USB stick, but also with CD-ROM. In this case, could you update the bug title.
If issue is due to presence of SD card at start, why not removing SD card at start and hot-plug it after boot and before install ?
About mass memory enumeration, there are some issues since 10.10 as BIOS and some other software don't use same order (including Grub).