qwqwqw, you shouldn't need all those kernel flags.
I discovered the cause of the loud beeping - apparently FakeCPUID does something the kernel doesn't like. Enabling the KernelCpu patch seems to be sufficient to get Yosemite to boot. However, bus speed is still a problem. The "tsc_init: EFI not supported!" panic occurs when the timer frequency is misdetected or set to zero by the line of code that ensures the FSB is above 90MHz but below 10GHz. The only way I'm aware of to set BusSpeedkHz or let the bootloader auto-detect the FSB frequency without interference from the kernel is to patch the kernel, by either modifying or removing the FSB frequency check in the code snippet I posted above. Without the XNU kernel source for OSX Yosemite and without the compiler toolchain, which AFAIK is Mac-only - yay for chicken/egg problems! - I've had to resort to binary patching. I got this far on Yosemite:
sudo perl -pi -e 's|\x48\x8d\x83\x7f\xb5\xa2\xfa|\x48\x8d\x83\xaf\xbb\xbb\xfb|' /path/to/kernel
sudo perl -pi -e 's|\x48\xb9\x7f\x99\xae\x4e\x02|\x48\xb9\xaf\x9f\xc7\x4f\x02|' /path/to/kernel
sudo perl -pi -e 's|\x48\x3d\x81\x4a\x5d\x05|\x48\x3d\x51\x44\x44\x04|' /path/to/kernel
sudo perl -pi -e 's|\x41\xc7\x47\x14\x80\x4a\x5d\x05|\x41\xc7\x47\x14\x50\x44\x44\x04|' /path/to/kernel
I probably miscalculated terribly because the problem persists with or without the above patches. Those 4 lines replace occurrences of the reverse hex representation of 90M (line 1), a confusing combination of 10G-90M (line 2), 90M+1 (0x55d4a81, line 3) and plain old 90M (0x55d4a80, line 4), respectively, with an arbitrary value, 0x4444450 (71582800). In theory, this should lower the minimum allowed bus frequency to 71MHz so that this laptop, and presumably others using newer Bay Trail/Valley View based Atoms, Pentiums and Celerons, can boot with a bus frequency lower than 90MHz. Of course, in practice, I suck at math and am likely to have done something terribly wrong.
Those last two lines occur nowhere near other TSC code, so they probably shouldn't be applied anyway.
I haven't tested these patches on a Mavericks kernel either - they're unlikely to work, even though I performed what I consider to be all the required sorcery.
I did try to make sure none of those values occur elsewhere in the code. The above patches should apply to both the 10.9 and 10.10 kernel and they're reversible, but I'd recommend keeping a copy of the vanilla kernel handy if you want to have a go at this.
For anyone interested in checking my disassembly analysis/calculations, I used GNU binutils (x86_64-apple-darwin-objdump -D) on Ubuntu Linux configured with Darwin as the target platform:
sudo apt-get install build-essential git bison flex texinfo
git clone git://sourceware.org/git/binutils-gdb.git binutils
./configure --prefix=/usr/local --target=x86_64-apple-darwin --enable-64-bit-bfd --disable-nls --disable-werror
make && sudo make install