This is not your firmware. This is the bootstrap program in the Volume Boot Record of an NTFS volume. It is trying to read the
BOOTMGR file (or the
NTLDR file), but is unable to. The VBR bootstrap program is not a full filesystem driver, and so isn't capable of handling things such as compressed NTFS files.
Normally, this isn't a problem, since Microsoft's tools try to avoid compressing the
NTLDR files. It is however possible to end up in a situation where those files are compressed. (Hewlett Packard indicates that one could restore these files from backup onto an NTFS volume that one has chosen to enable compression on, for example.) You simply need to decompress the files, in this case. One can do this by bootstrapping another installation of Windows NT, or the Windows Recovery Environment, and either turning off compression for the volume that those files are on, or decompressing the specific files.
The string "BAXOS" should actually be "NTLDR". Sometimes it isn't, though, and all sorts of five-letter combinations have been reported. When it isn't, this indicates that the reason that the bootstrap loader program thinks that the file is compressed is not that it actually is compressed, but that something has gone and scribbled random nonsense all over the volume, mucking up the MFT entry for the file as well as things in the first sector. (Volume corruption isn't the sole explanation. There's a possible way for a badly written rootkit malware to end up placing the system in this state. I've not seen it discussed in public, however.) In this case,
chkdsk of the volume is called for, as the first stop.