We present reprocessed flux-calibrated spectra of 406 stars from the UVES-POP stellar library in the wavelength range 320-1025nm, which can be used for stellar population synthesis. The spectra are provided in the two versions having spectral resolving power R=20000 and R=80000. Raw spectra from the ESO data archive were re-reduced using the latest version of the UVES data reduction pipeline with some additional algorithms that we developed. The most significant improvements in comparison with the original UVES-POP release are (i) an updated echelle order merging, which eliminates "ripples" present in the published spectra; (ii) a full telluric correction; (iii) merging of nonoverlapping UVES spectral setups taking into account the global continuum shape; (iv) a spectrophotometric correction and absolute flux calibration; and (v) estimates of the interstellar extinction. For 364 stars from our sample, we computed atmospheric parameters Teff, surface gravity logg, metallicity [Fe/H], and {alpha}-element enhancement [{alpha}/Fe] by using a full-spectrum fitting technique based on a grid of synthetic stellar atmospheres and a novel minimization algorithm. We also provide projected rotational velocity vsini and radial velocity vrad estimates. The overall absolute flux uncertainty in the reprocessed data set is better than 2%, with subpercent accuracy for about half of the stars. A comparison of the recalibrated UVES-POP spectra with other spectral libraries shows a very good agreement in flux; at the same time, Gaia DR3 BP/RP spectra are often discrepant with our data, which we attribute to spectrophotometric calibration issues in Gaia DR3.