Source package tboot-1.7.3.tar.gz can be downloaded from sourceforge.net.
And since 1.7.3 the upstream repository was moved to:
Major changes since 1.7.2 (20120929):
Update README with updated code repository url.
Fix grub2 scripts to be compatible with more distros.
Update README for RACM launch support
Add a new option "call_racm=true|false" for revocation acm(RACM)
Fix potential buffer overrun & memory leak in crtpconf.c
Fix a potential buffer overrun in lcptools/lock.c
Print cmdline in multi-lines
Optional print TXT.ERRORCODE under level error or info
Fix side effects of tboot log level macros in tools
Update readme for the new detail log level
Classify all logs into different log levels
Add detail log level and the macros defined for log level
Fix acmod_error_t type to correctly align all bits in 4bytes
Please help testing it, and enjoy it.